I deleted my partition for windows 8.1 and also the image file installing Ubuntu. What I wanted to do was install Ubuntu alongside Windows using half my disk space. Is there any possible way to recover windows 8.1 other than purchasing it?  *First installed OEM installer then regular version also tryin to install and run some iso files on my system
I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.
How can I display additional boot and shutdown information on the Windows 7 welcome screen? There is a small tweak, I believe it is a registry key, that allows to display additional information on the Welcome and Shutting down screens of Windows 7 (and most likely Vista, too). I have activated this tweak on one of my systems; unfortunately I forgot how I did it, and I can't seem to find the website that originally gave me that information.  Usually, the Windows 7 welcome screen will just display "Welcome" when logging in. With the tweak activated, my Welcome screen gives status information such as "Loading user settings" or "Preparing desktop". When shutting down, the default screen simply says "Shutting down". With the tweak activated, it gives additional status information such as "Stopping Windows services". This appears the same way that Windows gives information when updates are installed or configured during the startup or shutdown procedure, and I find them quite helpful in getting a feel for what task takes how long during that process.  The only setting I was able to find is the Boot log checkbox on the Boot tab of the msconfig application. However, this results in Windows displaying console logs of drivers it is loading, etc., instead of the animated Windows title. This is NOT the setting I am looking for. The "additional boot information" setting that I have activated on this system still displays the regular animated Windows logo, and only replaces the strings displayed on the blue Welcome and Shutdown screens.  Could someone direct me to the registry key (or whatever setting) that is used to get this behaviour?  Edit: Here are a few pictures of the enhanced Welcome and Shutdown screens taken with my mobile phone—they're in German though.   Login screen "Waiting for User Profile Service"   Login screen "Preparing desktop"   Logout screen "Stopping Windows services": Marketing Cloud contact builder shows 9 times more contacts Does the speed of light vary in non-inertial frames? The speed of light is the same in all inertial frames.  Does it change from a non-inertial frame to another? Can it be zero?  If it is not constant in non-inertial frames, is it still bounded from above? Fitting a plane to a set of points in 3D using PCA I am trying to estimate a midplane of a 3D model using the midpoints of paired landmarks, in order to reconstruct missing data (midplane refers here to the middle/saggital plane of the cranium which cuts the skull into two symmetrical halves, left and right).  I therefore need to estimate a plane from 27 points in 3D. I need to get the equation of the plane as $$ax+by+cz=d.$$  I have looked into orthogonal regression and principal component analysis (PCA) as methods, however I didn't take maths past A-levels and am struggling. I know I can supposedly use the eigenvectors to get the equation of the plane of best fit, but need someone to explain exactly how. I am using R for the PCA but am not great at R either.  Alternatively, if there's a better way to estimate the plane I would be glad to hear it! What version of Ubuntu should I pick? I'm just a simple user frustrated with Windows 10 and I want to leave Windows altogether.  However, I don't want to spend three weeks learning how to install the new system and then get all my current programs to work.  I am not setting up a server, I am not a developer and I do not want all my stuff on a cloud. Why is mathematical induction a valid proof technique? This question is similar to      and    except that I am concerned with smooth manifolds. If $M$ is a smooth manifold and $V$ and $W$ are (smooth, real) vector bundles on $M$, are there reasonable conditions that ensure that the map $\Gamma(M,V)\otimes_{\mathscr{O}_M(M)}\Gamma(M,W)\rightarrow\Gamma(M,V\otimes W)$ is an isomorphism? Equivalently, are there any reasonable conditions under which taking global sections of finite locally free $\mathscr{O}_M$-modules commutes with tensor product?  I don't really know much smooth manifold theory, and my intuition is mostly derived from algebraic geometry, where the analogous question, as is indicated in the questions I linked to, is not a simple one, even for invertible sheaves. I'd always assumed the situation for smooth manifolds would be the same, but I was just looking at the Wikipedia page on vector-valued differential forms, and it seems (unless I'm misunderstanding which is certainly possible) to claim there that for $V$ an arbitrary vector bundle and $W$ the $p$-th exterior power of the cotangent bundle, $p\geq 1$, the answer to my question is "yes," with the justification being that "$\Gamma(M,-)$ is a monoidal functor." Looking at the definition of a monoidal functor, it seems to me that all this implies is that there is a map from the tensor product of the global sections to the global sections of the tensor product (which is clear from the definitions) and not that this map is an isomorphism. Module 'pdftexcmds' not found after update Yesterday I updated my distribution (tlmgr update --all) and now I cannot use TikZ with lualatex anymore.  Minimal working example:  \documentclass{article} \usepackage{tikz} \begin{document} a \end{document}   Compilation output:  &gt; lualatex a This is LuaTeX, Version 1.10.0 (TeX Live 2019)                                                                                                                                                                         restricted system commands enabled.                                                                                                                                                                                  (./a.tex                                                                                                                                                                                                              LaTeX2e &lt;2019-10-01&gt; patch level 3                                                                                                                                                                                     luaotfload | main : initialization completed in 0.098 seconds                                                                                                                                                         (/opt/texlive/2019/texmf-dist/tex/latex/base/article.cls                                                                                                                                                              Document Class: article 2019/10/25 v1.4k Standard LaTeX document class                                                                                                                                                (/opt/texlive/2019/texmf-dist/tex/latex/base/size10.clo))                                                                                                                                                             (/opt/texlive/2019/texmf-dist/tex/latex/pgf/frontendlayer/tikz.sty                                                                                                                                                    (/opt/texlive/2019/texmf-dist/tex/latex/pgf/basiclayer/pgf.sty                                                                                                                                                        (/opt/texlive/2019/texmf-dist/tex/latex/pgf/utilities/pgfrcs.sty              ...  (/opt/texlive/2019/texmf-dist/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex (/opt/texlive/2019/texmf-dist/tex/generic/pgf/libraries/pgflibraryplothandlers. code.tex) (/opt/texlive/2019/texmf-dist/tex/generic/pgf/modules/pgfmodulematrix.code.tex)  (/opt/texlive/2019/texmf-dist/tex/generic/pgf/frontendlayer/tikz/libraries/tikz librarytopaths.code.tex))) No file a.aux. ABD: EveryShipout initializing macros (/opt/texlive/2019/texmf-dist/tex/context/base/mkii/supp-pdf.mkii [Loading MPS to PDF converter (version 2006.09.02).] ) (/opt/texlive/2019/texmf-dist/tex/latex/epstopdf-pkg/epstopdf-base.sty[\direc tlua]:1: module 'pdftexcmds' not found:         no field package.preload['pdftexcmds']         [kpse lua searcher] file not found: 'pdftexcmds'         [kpse C searcher] file not found: 'pdftexcmds' stack traceback:         [C]: in function 'require'         [\directlua]:1: in main chunk. l.165       \directlua{require("pdftexcmds")}  ?    It seems that a Lua package is missing.  Is this a bug? Am I missing a package? Totally ordering the power set of a well ordered set. Let's say I take a set $S$, where $S$ can be well ordered. From what I understand, one can use that well ordering to totally order $\mathscr{P}(S)$.  How does a body actually use the well ordering of $S$ to construct a total ordering of $\mathscr{P}(S)$?  Perhaps construct is too strong a word. Is there a way to prove that a total ordering of $\mathscr{P}(S)$ just exists, no need to explicitly state what it is, since that might be very difficult. Let $E$ be a Banach space, $\mathcal B(E)$ the Banach space of linear bounded operators and $\mathcal I$ the set of all invertible linear bounded operators from $E$ to $E$. We know that $\mathcal I$ is an open set, and if $E$ is finite dimensional then $\mathcal I$ is dense in $\mathcal B(E)$. It's not true that $\mathcal I$ is dense if we can find $T\in\mathcal B(E)$ injective, non surjective with $T(E)$ closed in $E$, since such an operator cannot be approximated in the norm on $\mathcal B(E)$ by elements of $\mathcal I$ (in particular $E$ has to be infinite dimensional).  So the question is (maybe a little vague): is there a nice characterization of $\overline{\mathcal I}^{\mathcal B(E)}$ when $E$ is infinite dimensional? Is the case of Hilbert space simpler? Prove that the dihedral group $D_4$ can not be written as a direct product of two groups I read in a book &quot;Physics - Resnik and Halliday&quot; the explanation of Type-I Superconductors {cold ones} that:  The Electrons that make up current at super-cool temperatures move in coordinated pairs. One of the electrons in a pair may electrically distort the molecular structure of the superconducting material as it moves through, creating  nearby short-lived regions of positive charge.the other electron in the the pair may be attracted to the positive spot. According to the theory the coordination would prevent them from colliding with the molecules of the material and thus would eliminate electrical resistance  Is this the only explanation or can somebody give me a more intuitive explanation that also takes into the problem of defect scattering as in the case of resistance and also explains the Type-II superconductors {hot ones} P.S. What are &quot;coordinated pairs&quot;? SF novel about one-way scientific expedition to inhabited planet, where telepathic aliens "talk" sort of ++like this++ and ~*~this~*~ I'm looking for a novel I read in the mid-to-late 1990s. It was a science fiction novel about an expedition of scientists sent at sub-light-speed (maybe in cryo-sleep?) to investigate a star system. Once there they set up a permanent scientific outpost.  There was at least one inhabited planet in the system, with a sentient species that communicated telepathically. The aliens' speech was represented with various symbols instead of quotation marks, with each named character having (I think) its own characteristic set of symbols, as in the title of the question. The scientists are eventually able to communicate with these (generally friendly) aliens.  The thing I remember most clearly is the end of the book. This was a one-way trip for the scientists, so gradually they all die off from various causes. When the next-to-last member of the crew dies of old age, the survivor is looking for an epigraph for her funeral, and (ironically, considering my current plight) can't find it in his search of the electronic library. He finally discovers it under "humor" because it's by Mark Twain: "Wherever she was, there was Eden." (This quote, of course, I found immediately in  and many other sources; it's from Eve's Diary.)  Other pieces of information I'm less sure of:   I don't think the planet was hospitable to humans; it may have been something like a gas giant, with the aliens "swimming" through the gas. I think the scientists stayed in an orbital space station, though they may have made expeditions to the planet in vehicles or protective suits. There may have been a "twin" planet, or a moon in an eccentric orbit, that caused periodic "flares" of some sort on the aliens' planet. There might have been some conflict between the crew early on, maybe because there was a non-scientific (military) commander, or perhaps just because people have conflict. I think the author was of sort of middling fame; respected and known by SF enthusiasts, but not a superstar like Asimov or Clarke. Almost certainly male, and probably with a professional science background. I think the science was fairly authentic, although the first-contact bit was obviously highly speculative. How to set Windows bootloader as default bootloader? I have a Win 7/11.10 dual boot system with Grub 2 as the default bootloader. However, I want to make Windows bootloader the default bootloader (grub 'dos' like interface scrares the hell out of my sister) so when I start the PC I will have the following boot options: 1. Windows 7 2. Ubuntu  NB: A process to reverse this operation so Grub can be the default bootloader again will also be appreciated Why is the notation $\frac{\partial f}{\partial x}$ used? What's the difference between MathOverflow & Mathematics.SE? If I have a maths question, on which site should I ask:  or ? Reason for Subject-Verb Inversion: Only in cases where A is B, shall the Company do X Protect .NET code from reverse engineering? What's the fixed size of the suggested edit queue? Using the residue theorem, calculate $\int_{0}^{2\pi}\frac{1}{1-2a\cos{\theta}+a^2}d\theta$