My PC was infected by belombrea. I was told to reinstall OS, but I did it a different way. Is this sufficient?  Go to the search bar, type reset, click reset this PC. It'll give 3 options. On the bottom there's more recovery options with "learn how to start fresh with a clean installation of Windows PC", is that the same as reinstalling the OS? If I try click, it'll tell me that I'll need to reinstall Dell Touchpad, Realtek Card Reader &amp; Realtek High Definition Audio Driver from the web. How can I do that?
What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits.
Counting number of vertices of polygons and lines in QGIS? In QGIS, is there a way to count the number of vertices of polygons and lines in a given layer, and create a separate field containing these values?   I suspect it's a function somewhere in the field calculator but I can't find it. Command-line mv exclusion list Let $(X, Y)$ be distributed as a multivariate normal with parameters  $$ \mu = \begin{bmatrix} \mu_X \\ \mu_Y \end{bmatrix} \qquad \Sigma = \begin{bmatrix} \sigma_X^2 &amp; \sigma_{XY} \\ \sigma_{XY} &amp; \sigma_Y^2 \end{bmatrix}. $$   I would like to calculate $E(X | y_1 &lt; Y &lt; y_2)$, where $y_1$ and $y_2$ are constants.  From , I have managed to work out that $$ E(X | Y &gt; y_1) = \mu_X + \frac{\sigma_{XY}}{\sigma_Y} \left[\frac{\phi\left(\frac{y_1 - \mu_y}{\sigma_Y}\right)}{1 - \Phi\left(\frac{y_1 - \mu_y}{\sigma_Y}\right)}\right]\\ E(X | Y &lt; y_2) = \mu_X - \frac{\sigma_{XY}}{\sigma_Y} \left[\frac{\phi\left(\frac{y_2 - \mu_y}{\sigma_Y}\right)}{\Phi\left(\frac{y_2 - \mu_y}{\sigma_Y}\right)}\right] ,$$ where $\phi(\cdot)$ and $\Phi(\cdot)$ are, respectively, the p.d.f. and the c.d.f. of the Normal distribution. I could not figure out how to calculate $E(X | y_1 &lt; Y &lt; y_2)$, though.  I have searched for an answer in similar posts from the Stack Exchange network, but I couldn't get a clue from them that would solve this issue. For the record, here are some of them: If $M$ isn't Noetherian, $M$ has a submodule maximal with respect to being not finitely generated. I'm answering this question:     Let $M$  be a module. Show that if  $M$ is not Noetherian then $M$ has a submodule $N$ such that $N$ is not finitely generated but $A$ is finitely generated whenever $N &lt; A ≤ M$.   The solution starts as follows (I'm following a given solution): Let $Y$ be the set of non-finitely-generated submodules of $M$. If $(N_α)$ is a chain in $Y$ then $Q= \bigcup_αN_α $ is in $Y$, else $Q$ is f.g., which implies $Q=N_α$ for some $α$, whence $N_α$  is f.g., contradiction.  I don't understand why if $Q$ is f.g., then $Q=N_α$ for some $α$? Am I missing some fact?  Thanks! pdfTeX error (font expansion): auto expansion is only possible with scalable How to know if Mac OS X machine is being remotely viewed? Currently I have no way to know if my machine is being remotely viewed by our tech support, and would prefer to know, given the massive privacy breach that would entail should this be happening. I am running Mac OS X Snow Leopard.  Running  ps -A | grep Remote   I know this service is running:  /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent   My knowledge of administration of Macs on a network is limited, so I don't know what tools allow this. How to simulate data that satisfy specific constraints such as having specific mean and standard deviation? Suppose $A$ is a $n \times n$ constant matrix. How can I prove $\det(e^A) = e^{\displaystyle \sum_{\lambda_i\in\sigma(A)} \lambda_i}$,  where $\sigma(A)$ is the multiset of eigenvalues of $A$?  The following matlab code shows this is true in $n = 3$ case:  A = rand(3) detA = exp(sum(eig(A))) detmA = det(expm(A)) I found some articles related to this, but they were not sufficient for me. I want to know how the localhost works and why is it the same on many different machines?   How does the localhost block the access to the website when we use it in the host file to block the website? Why does my material panel look different? Complete beginner here.  I'm trying to follow  tutorial on Anisotropic shaders, but my property panel looks nothing like the property panel in the tutorial.  For example, when creating a material, this is what his property panel looks like:    But this is what mine looks like, if I follow the same path:    I'm sure I'm missing something obvious.  How can I see the property panel shown in the tutorial? Does the sequence $\{\sin^n(n)\}$ converge?   Does the series $\sum\limits_{n=1}^\infty \sin^n(n)$ converge? Express solutions of equation $ \tan x= x $ in closed form I know that the equation $$ \tan(x) = x $$ can be solved using numerical methods, but I’m looking for a closed form of the solutions. In my opinion, having only numerical solutions means that we don’t know the problem, and sooner or later, we’ll be able to find a closed-form solution or at least a power-series solution. I’m looking for an explicit form of a sequence $ (x_{n})_{n \in \mathbb{Z}} $ in $ \mathbb{R} $ such that  $ 0 &lt; x_{0} &lt; \dfrac{\pi}{2} $, $ \tan(x_{n}) = x_{n} $ for all $ n \in \mathbb{Z} $, and $ (2 n - 1) \dfrac{\pi}{2} &lt; x_{n} &lt; (2 n + 1) \dfrac{\pi}{2} $ for all $ n \in \mathbb{Z} \setminus \{ 0 \} $.  The existence of such a sequence follows from the continuity of $ x \mapsto \tan(x) - x $ over its domain. Its uniqueness follows from the monotonicity of $ \tan(x) - x $ over the intervals $$ \left( (2 n - 1) \frac{\pi}{2},(2 n + 1) \frac{\pi}{2} \right), \quad n \in \mathbb{Z}. $$ How do you find time period as a function of time for a simple pendulum that is in the form of a hollow sphere that is filled with mercury and there is a hole in the bottom through which the mercury is constantly falling at a fixed rate? I tried creating a function for the time period to check how it varies with the mass of mercury, but I had too many variables.   EDIT: This question was a concept based multiple choice question in my homework book. The option were time period becomes erratic, time period increases, time period decreases, time period first increases then decreases. How do I access $HOME/storage Termux directory on Android Pie with a GUI File Explorer?  In Termux I print the working directory with pwd and it shows $HOME/storage as:  /data/data/com.termux/files/home   My internal storage looks like this:  . ├── Alarms ├── Android |   ├──data |   |  ├── ... |   |  ├── com.termux |   |  |   └── files |   |  |       └── 0 items |   |  └── ... |   └── ... ├── DCIM ├── Download └── ...   My external storage looks like this:  . ├── Android |   ├──data |   |  ├── ... |   |  ├── com.termux |   |  |   └── files |   |  |       └── 0 items |   |  └── ... |   └── ... └── LOST.DIR   Neither my internal storage, nor my sd card, contain a /data/ directory at the root level. Where is this /data/ directory? For that matter, where is the root /storage/ directory? Where is the root /emulated/ directory? Where are any of these directories and why cant I access any of them? Insert results of a stored procedure into a temporary table Legitimate edits of less than 6 characters I recently came across an  by  which contained a link to a specification that has since been moved. When attempting to edit the link, a change which involved the subtraction of only 4 characters, I ran up against the 6 character minimum requirement.  Ordinarily this would not be an issue. A less experienced poster would likely have other things within the answer that could be changed (). In fact, this seems to be the answer on every meta post relating to this topic (, , etc...).  The problem here, since I don't have 2k reputation, is that BalusC writes excellent answers... with the reputation to back them up. I don't feel there is anything in the post (besides the link) that would benefit from me editing.  What is the standard practice here?   Flag the post and explain my situation in the notes (for someone with higher reputation)? Comment on the post and hope that a) visitors read the comments or b) the OP gets notified and updates their post? Make edits, for the sole purpose of increasing characters, providing no benefit and possibly hurting the quality of the post?   For reference, the EL Specification in the post should be changed to , if someone wants to go ahead and take care of this. There is this puzzling thing that is called : paradoxically, warm (35°C) water freezes faster than cold (5°C) water.  As a physisist, I've been asked about it several times already. And I have no definite answer to that, apart from the standard: "there are many things that can influence it".  So, does anyone knows about the status or progress on that effect? Any recent reviews, publications or other references? What is the best way to filter a Java Collection? I want to filter a java.util.Collection based on a predicate. How to return multiple objects from a Java method? "is" operator behaves unexpectedly with integers Why does the following behave unexpectedly in Python?  &gt;&gt;&gt; a = 256 &gt;&gt;&gt; b = 256 &gt;&gt;&gt; a is b True           # This is an expected result &gt;&gt;&gt; a = 257 &gt;&gt;&gt; b = 257 &gt;&gt;&gt; a is b False          # What happened here? Why is this False? &gt;&gt;&gt; 257 is 257 True           # Yet the literal numbers compare properly   I am using Python 2.5.2. Trying some different versions of Python, it appears that Python 2.3.3 shows the above behaviour between 99 and 100.  Based on the above, I can hypothesize that Python is internally implemented such that "small" integers are stored in a different way than larger integers and the is operator can tell the difference. Why the leaky abstraction? What is a better way of comparing two arbitrary objects to see whether they are the same when I don't know in advance whether they are numbers or not?