I'll start by saying, I am asking this question after having read most of the similar threads out there and tried what they suggest but with no luck.  So, I have this laptop .  I had Windows 7 installed but I erased them and I only have Ubuntu now.  When I restart my laptop and right after the Asus starting screen I get a black screen with a flashing underscore.   Editing grub file - Does not work. Shift key pressed or spammed - Does not work. Whole keyboard spammed - Works some times.   So what are your opinions? Any suggestions? Cause it's annoying to spam the whole keyboard every time, plus it's not a guaranteed solution.  Edit: Common fixes that worked for others like reinstall grub, run boot-repair, keys pressed during startup do not work in my case. I'm not an expert but I think it either is my graphics card (I don't know why but I've seen it being mentioned in other threads) or it's like the system is not booting from the right partition. Partitions are as follow:/boot(flaged for boot), / "root", swap and /home.  Edit: Here is the report from the last repair-boot just in case....
I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?
Call C++ library in C# I have a lot of libraries written in C++. I want to call these libraries from C#, however, I have met many problems. I want to know if there is a book or guideline to tell me how to do that. How do I get adequate depth of field in macro photography? I have been messing around with some Macro Photography using the techniques (and a reversal ring) described in a  by @ My main issue is that I am having a hard time getting the subject into focus. There are times when the center is blurred and the outside is in focus or the center in focus and the outside out of focus. What are ways to get as much of the subject in focus?   I am using a Nikon D5100, I have a 18-55mm kit lens but I find the 55-200mm lens easier to use for shooting. What is JavaScript's highest integer value that a number can go to without losing precision? Help me identify this insect from Bangladesh I have seen this insect flying literally everywhere in Dhaka city (Bangladesh) over the last two months. It's small -- around 1-1.5 inches long. It's not an agile flyer and can be easily grabbed by hand during flight. Odd behavior in a QGIS plugin: my function is triggered twice I have a plugin with a function (triggered by a button) that selects a specific layer by name, then shows its attribute table. When I close the plugin and open it again, the attribute table pops up twice, and repeating this keeps adding another table popup. What's wrong?  Code:  def showTable(self):     for lyrs in QgsMapLayerRegistry.instance().mapLayers().values():         if lyrs.name() == "TestFeatures":             lyrTest = lyrs     self.iface.showAttributeTable(lyrTest) We can test the symmetry of a distribution around $0$ by Wilcoxon sign rank test, based on its sample.   But if we want to test if a distribution is symmetric around its mean, based on its sample $X_1, \dots, X_n$, is it valid to first normalize $X_i$ by the sample mean as $Y_i := X_i - \bar{X}$, and then apply Wilcoxon sign rank test to $Y_i$'s?  If not, what are some ways?  Thanks and regards! Is it coherent to extend $\mathbb{R}$ with a reciprocal of $0$? I'm sure this is an obvious question, but I'm having trouble finding the right words to type into Google.  I know that the definition of a ring allows that the additive identity not have a multiplicative inverse, but is this a requirement?  Specifically, is something like $\mathbb{R}\!\left[\frac{1}{0}\right]$ such that $\frac{1}{0} \cdot 0 = 1$ a ring, or does some contradiction arise from allowing the additive identity to have a multiplicative inverse? Secretary problem - why is the optimal solution optimal? I have read about this problem:    But I want to see how it is proven that the "optimal" solution is indeed optimal. I understand how to prove that if the optimal solution is of the form "wait for $t$ candidates and then choose the next best one" then $t=n/e$ is optimal; but why is the best strategy of that form in the first place?  A complete proof is not required - a reference to a good text discussing this is good as well. Installing a 16-bit Windows 95 game on 64-bit Windows 7 Home Premium Can the Artificer Artillerist's tiny-sized Eldritch Cannon that is not held in hand still ride or be carried elsewhere on the body? Convergence of the series $\sqrt[n]n-1$ Let $a_n=\sqrt[n]n-1$. Does $\sum_{n=1}^\infty a_n$ converge? I have a problem understanding the proof of Rencontres numbers (Derangements) Best way to merge mp4 files Does the (relativistic) mass change? Why? How do I know if an ability is magical? The validation tab in your script tool properties allows you to put parameters in categories. The :     Put parameters in different categories. Categories are expandable   window shades with a collection of parameters.     I am using the categories to organize my parameters, so I don't care about the expandable/collapsible feature;  it just adds a lot of time to the user.  This is all within a normal toolbox, not a script toolbox.  v10.1    Does anyone know how to have these categories expanded by default?  Here is my only validation code.  I am only utilizing categories.  The other parts are the default.  def initializeParameters(self):     """Refine the properties of a tool's parameters.  This method is     called when the tool is opened."""     self.params[0].category = "General"     self.params[1].category = "General"     self.params[2].category = "Inudaciones"     self.params[3].category = "Cienegas"     self.params[4].category = "DrenajesPrincipal"     self.params[5].category = "DrenajesSensillos"     self.params[6].category = "Inudaciones"     self.params[7].category = "Cienegas"     self.params[8].category = "DrenajesPrincipal"     self.params[9].category = "DrenajesSensillos"     return Given $n+1$ points in the plane, Lagrangian interpolation gives the unique polynomial of degree less or equal to $n$.  From the examples I've seen so far, interpolation polynomials all have degree exactly $n$ but I don't know if there might be a set of points for which the interpolation gives a polynomial of degree strictly less than $n$.  Many thanks for your answers. Finding package name of installed software Since I have not been able to open Dash Home in 12.04.4 see , I am hoping for a work-around. Is there another convenient way to open apps/programs without having to search through folders? Is this question clear enough? For example, I just installed Kile (publishing program) from the Software Center, but I can't find a link/tile/icon/shortcut to open it. Thanks, to whomever can help. Now this might be a very stupid question for many readers, but I am getting really confused.   I was reading about electricity and current, and I read this:  Suppose we connect a wire to the ends of a battery, and a bulb in the circuit, current flows and lights up the bulb. The battery is responsible for doing work on the positive charges to move them from negative terminal to positive terminal, that is moving against the field. Now, these energised positive charges move through the external circuit, and within the circuit they give some of their energy to light the bulb. I understood this very well.  Now, reading further, it was written that "Electrons are actually responsible for current flow". It was written that there is concentration of energised negative charges on the negative terminal, and these electrons then move through the external circuit from negative to positive terminal. This is really confusing.     So my question: What actually flows? The negative charge or the   positive charge?   Further reading, I also read that in semi-conductors, fluorescent light bulbs etc., both charges move through the circuit.     Now, one more doubt: If both charges move through the circuit in this   case, shouldn't the charges stop in the middle of the wire, because   opposite charges will attract each other, hence stopping their   movement? Institute Name in @masterthesis Citations I need to cite master thesis and the lecture notes into a document. But the problem with @masterthesis and @unpublished citations is they don't print an institution name in the pdflatex output of bibliography.   `\documentclass{article}   \usepackage{filecontents}  \usepackage[ backend=biber, style=numeric, sortlocale=de_DE, natbib=true, url=true,  doi=true, eprint=false ]{biblatex} \addbibresource{bibliography.bib}  \begin{filecontents}{bibliography.bib} @masterthesis{bhgt, title={Bike Model}, author={Fris}, year={2016}, school={University A}, address={XXX} } @unpublished{Map, title = {Electrical Engineering Book}, author={Koch}, howpublished = {Lecture Notes}, Institution= {University B}, year = {2015} } } \end{filecontents}  \begin{document}  Citation Test:  \cite{bhgt} and \cite{Map} \printbibliography  \end{document}`   I get this bibliography output:         [1] Fris. Bike Model. XXX, 2016.   [2] Koch. “Electrical Engineering Book”. Lecture Notes. 2015.       Any suggestions, how we can also print an institute name?