The installation went fine until I restarted. I remember enabling boot from removable disk and was thinking of disabling it as it boot up. Pressed F8 nothing happened. Instead it went straight to the Purple Ubuntu loading screen. If I try to boot without the usb, it just gives me a blank black screen with a blinking _.   I am fairly new to this and I am hoping for a fix. Thanks in advance.
I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:
Area51 proposals are being advertised now all over the network? Save Illustrator as PDF with transparent background How much hard disk space should be needed for Xbox 360? I want to get a 360 and don't know wether to get the bigger (250GB), newer, more expensive Elite, or get one of the older, smaller (120GB), last gen ones. I know the arcade is going to be too small to save anything useful  How much hard disk space is recommend? What else is stored besides games? Filtering points in GeoServer layer ContourPlot of implicit function doesn't work when I square the equation Do circular wheels maximize mechanical efficiency? I recently wondered whether there is a simple proof that circular wheels maximise mechanical efficiency. By this I mean:     Show that for a wheel with a given width and cross-sectional area, the   circular wheel reaches the bottom of an incline faster than a wheel   with any other shape.   This sounds like a rather elementary problem in classical mechanics but I haven't found a proof of this fact in any of the classical mechanics texts that I have read.   Note 1: I assume that the distribution of mass is uniform across the wheel so comparable wheels will have equal mass.   Note 2: Dry friction is assumed to be present. Provide an easily discoverable way to get the full URL to an answer , clicking &quot;link&quot; &quot;share&quot; for anwers yields a short (traceable) URL in the &quot;share a link to this answer&quot; dialog, such as †:  These short URLs show no clue about the linked question whatsoever. Also, when different people use a short URL for the very same post, then the user id suffix makes those be different URLs for a browser. Such links will then not be shown as visited‡. I know how to get URLs that have a proper slug. But as I see  pop up on these sites (where referrals ), I assume many others just don't realize full URLs would be better for use on these sites themselves? Or many don't want to do the little effort to get the full URL? So: can we please have an easy way to get the full URL as well, in a way that is easily found for those who don't know about the different links? (Currently for questions, clicking &quot;link&quot; has the same effect. But then one can also right-click the title, or take the URL from the location bar, to get the full human-readable URL. Once, Jeff .)  † The short links for answers are not (yet) [automatically converted][6] into a clickable question title either, unlike links such as `https://meta.stackexchange.com/questions/74274/privacy-leak-in-permalink#75963`, which renders as https://meta.stackexchange.com/questions/74274/privacy-leak-in-permalink#75963 But I guess that will change soon.  ‡ On Meta the CSS for posts doesn't indicate such difference anyway, which is a different issue. Notation problem in integration: write $dx$ or ${\mathrm{d}}x$? Can I use a custom Splash screen? The default Splash screens are cool, but I'd like to add some of my own work to remind me of how awesome I am (no, not really).    Is it possible to customize/change the splash screen? Use $\delta-\epsilon$ to show that $\lim_{n\to\infty} a^{\frac{1}{n}} = 1$? Hope this is a meaningful question, but I'm curious if is possible to show that   $$\lim_{n\to\infty} a^{\frac{1}{n}}=1, \text{where  }a&gt;0$$  using $\delta-\epsilon$ directly or other methods. One method that I am aware of is to use the following:     If $\{s_n\}$ is a nonzero sequence, then $\liminf\bigl|\frac{s_{n+1}}{s_n}\bigr|\le \liminf |s_n|^{\frac{1}{n}}\le \limsup |s_n|^{\frac{1}{n}}\le\limsup\bigl|\frac{s_{n+1}}{s_n}\bigr|$ Is the Playstation 4 backwards-compatible? Does the PS4 have backwards compatibility of some form? The majority of forums/sites suggest not, or posters are adamant it doesn't yet. Others imply that some form of backwards compatibility will include a cloud service and PS3 titles? I've even heard on some forums that PS4 does actually play PS3 games but those posts seem to be a minority compared to those that say it's not... If all the roots of a polynomial P(z) have negative real parts, prove that all the roots of P'(z) also have negative real parts This seems to be a basic issue, but I just realized that I actually don't know how to test equality of coefficients from two different regressions. Can anyone shed some light on this?   More formally, suppose I ran the following two regressions:  $$ y_1 = X_1\beta_1 + \epsilon_1 $$ and  $$ y_2 = X_2\beta_2 + \epsilon_2 $$ where $X_i$ refers to the design matrix of regression $i$, and $\beta_i$ to the vector of coefficients in regression $i$. Note that $X_1$ and $X_2$ are potentially very different, with different dimensions etc. I am interested in for instance whether or not $\hat\beta_{11} \neq \hat\beta_{21}$.   If these came from the same regression, this would be trivial. But since they come from different ones, I am not quite sure how to do it. Does anyone have an idea or can give me some pointers?   My problem in detail: My first intuition was to look at the confidence intervals, and if they overlap, then I would say they are essentially the same. This procedure does not come with the correct size of the test, though (i.e. each individual confidence interval has $\alpha=0.05$, say, but looking at them jointly will not have the same probability). My "second" intuition was to conduct a normal t-test. That is, take   $$ \frac{\beta_{11}-\beta_{21}}{sd(\beta_{11})} $$  where $\beta_{21}$ is taken as the value of my null hypothesis. This does not take into account the estimation uncertainty of $\beta_{21}$, though, and the answer may depend on the order of the regressions (which one I call 1 and 2).   My third idea was to do it as in a standard test for equality of two coefficients from the same regression, that is take  $$ \frac{\beta_{11}-\beta_{21}}{sd(\beta_{11}-\beta_{21})} $$   The complication arises due to the fact that both come from different regressions. Note that   $$ Var(\beta_{11}-\beta_{21}) = Var(\beta_{11}) + Var(\beta_{21}) -2 Cov(\beta_{11},\beta_{21}) $$ but since they are from different regressions, how would I get $Cov(\beta_{11},\beta_{21})$?  This led me to ask this question here. This must be a standard procedure / standard test, but I cound not find anything that was sufficiently similar to this problem. So, if anyone can point me to the correct procedure, I would be very grateful! LOAD DATA INFILE easily convert YYYYMMDD to YYYY-MM-DD? Package Cache File corrupted From advice on  , I've opened a new question about the same issue, as it turned out my problem was not the one described in the question, information I did not know at the time. I'm running Ubuntu 16.04.  $ sudo apt-get update  Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease Get:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB] Get:3 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB] Get:4 http://archive.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Get:5 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 DEP-11 Metadata [307 kB] Get:6 http://archive.ubuntu.com/ubuntu xenial-updates/main DEP-11 64x64 Icons [226 kB] Get:7 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 DEP-11 Metadata [185 kB] Get:8 http://archive.ubuntu.com/ubuntu xenial-updates/universe DEP-11 64x64 Icons [268 kB] Get:9 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 DEP-11 Metadata [5,888 B] Get:10 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 DEP-11 Metadata [3,324 B] Get:11 http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 DEP-11 Metadata [4,712 B] Get:12 http://archive.ubuntu.com/ubuntu xenial-security/main amd64 DEP-11 Metadata [62.7 kB] Get:13 http://archive.ubuntu.com/ubuntu xenial-security/main DEP-11 64x64 Icons [71.2 kB] Get:14 http://archive.ubuntu.com/ubuntu xenial-security/universe amd64 DEP-11 Metadata [51.3 kB] Get:15 http://archive.ubuntu.com/ubuntu xenial-security/universe DEP-11 64x64 Icons [85.1 kB] Fetched 1,578 kB in 1s (1,529 kB/s)                                     Reading package lists... Error! E: Read error - read (5: Input/output error) W: You may want to run apt-get update to correct these problems E: The package cache file is corrupted   If there's any more information you need, don't hesitate to ask in the comments.  Edit 1:  $ sudo df -h Filesystem      Size  Used Avail Use% Mounted on udev            5.9G     0  5.9G   0% /dev tmpfs           1.2G  9.4M  1.2G   1% /run /dev/sda1       135G  7.2G  121G   6% / tmpfs           5.9G   14M  5.9G   1% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           5.9G     0  5.9G   0% /sys/fs/cgroup tmpfs           1.2G   88K  1.2G   1% /run/user/1000 /dev/sdb1       932G  300G  633G  33% /media/adoria298/MDrive1   Edit 2 SMART Test results: I was making a scene in blender and I wanted to change the texture from "Material_1" to "Material_2". It lets me change it but when I go to rendered view the part looks the same. can someone please help me I remember  due to misuse and I wonder if bots have a part of it. If the bot is POSTing something to my site what are ways I can combat it? I was thinking of setting some cookies and having the cookies changed via JavaScript + timestamp and sign (so yesterday's cookies can't be used today and next week).  I'm sure most people/bots would just use another site instead of enabling JavaScript in their bot.  What else can I do? I'm thinking daily POST limit and a honeypot for generic bots who just randomly post spam. Database design help. many-to-many relationship find exec '{}' not available after > Exec allows us to either pass all arguments at once with {} + or to pass them one by one with {} \;  Now let's say I want to rename all jpeg, no problem doing this:  find . \( -name '*.jpg' -o -name '*.jpeg' \) -exec mv '{}' '{}'.new \;   But if I need to redirect output, '{}' isn't accessible after redirection.  find . \( -name '*.jpg' -o -name '*.jpeg' \) -exec cjpeg -quality 80 '{}' &gt; optimized_'{}' \;   This wouldn't work. I'd have to use a for loop, storing find's output into a variable before using it. Let's admit it, it's cumbersome.  for f in `find . \( -name '*.jpg' -o -name '*.jpeg' \)`; do cjpeg -quality 80 $f &gt; optimized_$f; done;   So is there a better way? I've occasionally noticed an OP who will edit their own question and destroy it completely, always leaving some kind of graffiti-like scrawl in its place.  This seems to happen on low-quality questions by low-rep users, and the moment of self destruction tends to occur after the question is closed or otherwise devolves into a communication breakdown between the poster and the community.  Here are some examples:        It seems like the poster usually does this in anger (1st and 3rd example), or else is just confused about how to delete their question (2nd example).  My question is about how this should be handled. In the past I wasn't sure, so I always flagged for mod attention. However I notice the solution on all of these was to just do a rollback (I did this myself on the 2nd example after nothing happened). Is this a good enough approach, or should a flag be used?  What about with particularly obnoxious users like in the third example, where the guy came back to do it again?