I have a Dell XPS 13 that originally had Windows, but I removed it because I wanted to use Ubuntu. Unfortunately after some time I started having issues with the Wifi (which are a common problem with this laptop) and have decided to resintall windows.  Can I use the OEM key for activating it?  At some point the official Dell support changed a part of my pc because it was making a lot of noise and I was giving a paper with the new OEM key used to activate it.
I got a new laptop; it came with an existing Windows installation, but I wanted to migrate my current backup to the new machine. I dd-ed the new machine's partitions to an external drive:  /dev/nvme0n1p1 /dev/nvme0n1p2 /dev/nvme0n1p3 /dev/nvme0n1p4   and afterwards move my current partitions to the new machine. What followed was a medium-sized nightmare. The new machine would boot, but the wireless network drivers were not recognized and later found out (to the best of my knowledge) they couldn't be installed. I tried:   booting from the console and running:  sfc /scannow chkdsk C: /f /r /x   both seemed to have completed successfully, but now the machine would get stuck in a startup repair loop. I tried resetting the machine (whilst keeping my files), but this failed halfway through. now the machine's still stuck in the loop and decided to try and repair it externally using a bootable Windows&nbsp;10 . It's likely that I'll need the new machine's Windows&nbsp;10 key. I'm not sure if it's stored in the BIOS (it came with Windows&nbsp;10  preinstalled) or somewhere on the partitions.   How can I get the key from the partitions (if it's there at all) while booting from a Linux image?
Why is integration so much harder than differentiation? I have a dataset in csv file format that I'm loading into pgfplotstable. I can't change the format of the original csv, and being financial data it has a column of item names and two or three explanatory data points at the top of the table. e.g.  \documentclass{article} \usepackage{array,datatool,pgfplotstable}   \begin{filecontents}{sample.csv}     item,2008,2009,2010,2011      ,Actual,Actual,Forecast,Forecast      ,GBP,GBP,GBP,GBP      ,('000),('000),('000),('000) rounded     Area 1 OP, 1000000,1500000,1750000,250000     Area 2 OP, 400000,500000, 450000,-50000     Area 51 OP, 300000,375000,390000,15000     No P, 1250000, 1000000, 950000, 50000     Residuals, 800000, 80000, 90000, 10000   \end{filecontents}  \pgfplotstableread[col sep=comma]{sample.csv}\mystuff   I'm stumped at the next stage which is to typeset \mystuff so I have comma separators and can add a row that sums the 'Area' columns. At the moment to display the table I have to do something like  \begin{document}  \pgfplotstableread[col sep=comma,header=false]{sample.csv}\mystuff  \pgfplotstabletypeset[   columns/0/.style={string type},   columns/1/.style={string type},   columns/2/.style={string type},   columns/3/.style={string type},   columns/4/.style={string type}]\mystuff  \end{document}   How do I tag the top three rows as string and the rest of the last four columns as integer type so I can format and transform them? I haven't had the chance to take any serious low-level programming courses in school. (I know I really should get going on learning the "behind-the-scenes" to be a better programmer.) I appreciate the conveniences of Java, including the ability to stick anything into a System.out.print statement. However, is there any reason why you would want to use System.out.printf instead?   Also, should I avoid print calls like this in "real applications"?  It's probably better to  to print messages to the client's display using some kind of UI function, right? What is the difference between $* and $@? Emacs text-scale-adjust causes line numbers column to incrementally shrink and disappear I've set up emacs to display line numbers (global-linum-mode 1), and it works until I start enlarging the text via text-scale-adjust    The line numbers column starts to shrink, and disappears entirely after a few increments. When it has fully disappeared, further increments have no more effect on the left edge.    Is this a know issue? Is there a workaround?    Using GNU Emacs 23.1.1 in Ubuntu 10.04. Is an empty set equal to another empty set? I have a definition that claims that two sets are equal A = B, if and only if:  $\forall x ( x \in A \leftrightarrow x \in B)$  An empty set contains no elements. If I define the sets:  A = $\emptyset$  B = $\emptyset$  then can I conclude that A $\neq$ B? Since they contain no elements? Or would I have to show that an elements exists in one but not the other? To me it seems that these are not equal, but I'm struggling to wrap my head around this.  Thanks, Paul I couldn’t find any proof on the internet. I would appreciate an elementary proof , but any help would be appreciated!  Thank you. If a SHA256 hash with high entropy is then hashed with one made from low entropy, is the resulting hash higher/same/lower entropy? If one were to create a SHA256 hash using 256 coin flips converted to hex (which, as I understand it, is as "entro-phized" as one can capture in SHA256) then take that hash as a string, combine that with a hash of the word "cat" and hash the resulting 512 character string, would the resulting hash from that exercise be any less random than our "perfect" hash we began with?  My thinking is the final string would capture the same amount as the original randomness as what we started with because the "extra" entropy can not be captured and is lost. Is this the case and am I thinking about this correctly? Would hashing something with high entropy with something simpler ever cause a lower amount of randomness or does it only go up?  Thanks to anyone who can help explain this a little better. Show group of order $4n + 2$ has a subgroup of index 2. Let $n$ be a positive integer. Show that any group of order $4n + 2$ has a subgroup of index 2. (Hint: Use left regular representation and Cauchy's Theorem to get an odd permutation.)  I can easily observe that $\vert G \vert = 2(2n + 1)$ so $2 \mid \vert G \vert$ and 2 is prime. We have satisfied the hypothesis of Cauchy's Theorem so we can say $G$ contains an element of order 2.  This is where I am stuck  I am confused about how the left regular representation relates to the group. So my understanding at this point is that every group is isomorphic to a subgroup of some symmetric group. My question: is the left regular representation $\varphi : G \to S_G$ an isomorphism? where $G \cong S_G$ or is $S_G$ the same thing as $S_{\vert G \vert}$ and $\varphi$ is only an injection? I'm using Dummit and Foote for definitions.  I saw an argument online that said that since we have an element of order 2, there is a $\sigma \in S_G$ of order 2, but it is a product of $2n + 1$ disjoint 2-cycles. I don't understand how they could claim this and tried working it out on my own but didn't get there. -- They then went on to use the parity mapping $\varepsilon : S_G \to \{\pm1\}$ and since we have an odd permutation $\sigma$, we have $[S_G:\text{ker }\varepsilon] = 2$. I understood their computation but not how that directly shows that $G$ has a subgroup of order 2? unless $G \cong S_G$ because of how left regular representation is defined. (but again, I'm not understanding that concept very well yet.)  So, to be clear about my questions:   What is meant by left regular representation, is it an isomorphism or just an injection? and how would it be used here. If it is an isomorphism, the argument online starts to make more sense, but how can they say that since $\sigma$ is even, it is made up of $2n + 1$ disjoint transpositions? If you have a full, proof, I'd appreciate it, but good hints are just as good!   Thanks you! Equivalence Relation problem Let $S$ be the relation on $\mathbb{N} \times \mathbb{N}$ defined by $(a,b)S(c,d)$ if and only if $ad=bc$. Prove this is an equivalence relation on $\mathbb{N} \times \mathbb{N}$.  I think I've found this to be reflexive and symmetric, but I'm stuck on transitivity. Can someone check my work so far and assist with testing transitivity?  Reflexive: Let $(x,y)S(x,y)$. Then $xy = yx$. So $S$ is reflexive. Symmetric: Suppose $(a,b)S(c,d)$. Then, $ad = bc$. Therefore, $da = cb$ and $cb = da$. Therefore, $(c,d)S(a,b)$. Thus, $S$ is symmetric.  Transitive: Suppose $(a,b)S(b,c)$. Then $ac = bb$.   This is where I'm stuck. Any ideas? Make an object invisible to a specific camera? (Cycles) Clipped data frame clips labels? I have a large project with provincial data. The project is currently using a data driven map with a clipped data frame for the province. The issue is the data I'm trying to show is thousands of point labels within each province, and the now clipped border is clipping labels as well. How do I stop the labels from being clipped along with the data frame?  Also, I only want to show labels that are applicable to that specific province and not the neighbouring provinces. How do we know the brain flips images projected on the retina back around? Why do we turn images upside down again rather than dealing with them directly, still vertically rotated after passing through our lens?   I don't see how that would cause any problems, and how we'd ever be able to figure out if we are presented with flipped images after getting used to interacting based on visual input, whether flipped or not.   What am I missing? I have a speed-reading program I purchased with uses dotnet2. However, dotnet2 doesn't run on 64 bit wine. How would I install dotnet2? What is the best Java email address validation method? What are the good email address validation libraries for Java?  Are there any alternatives to ? I have an iPhone 6 128 GB which is not jailbroken. The current version of iOS on the phone is 8.1.3 and yesterday I wanted to update to iOS 8.2.  The download went through without any problem but while installing, it gave the error:     Unable to Install Update   An error occurred installing iOS 8.2   Tried installing after switching Off and ON and also tried Hard Reset (Holding Home button and On/off switch).  Same error displays every time.  Also the Touch ID has stopped working and I find that the Settings - Touch ID &amp; Passcode - iPhone Unlock is OFF.  When I try to switch it ON, the system displays the error     Failed   Unable to complete Touch ID setup. Please go back and try again.   Is anyone facing this problem?  I live in India. Reference for the subgroup structure of $\rm{PSL}_2(q)$ This material is covered in detail in Dickson's "Linear Groups with an exposition of the Galois Field Theory", chapter XXII and Huppert's "Endliche Gruppen", chapter II, paragraph 8. Since I don't speak german and Dickson's treatment often requires deciphering, I was wondering if there is a "modern" account of this somewhere. Integral $\int\frac{dy}{(y^2 + ay + b)^{3/2}}$ Need the indefinite integral with $a,b$ constants. This is not a homework question. Need it for a physics problem. Filesystem owner changed by mistake How to copy files via terminal? I have read about copying files with terminal but these examples will help me a lot. So here is what I want to do:  Examples:   I have a file in /home/levan/kdenlive untitelds.mpg and I want to copy this file to /media/sda3/SkyDrive and do not want to delete any thing in SkyDrive directory. I have a file in /media/sda3/SkyDrive untitelds.mpg and I want to copy this file to /home/levan/kdenlive  and do not want to delete any thing in kdenlive directory  I want to copy a folder from home directory to sda3 and do not want to delete any thing on sda3 directory and opposite I want to cut a folder/file and copy to other place without deleting files in that directory I cut it into.