I installed Ubuntu yesterday via a bootable USB drive, created with unetbootin. Everything went very well, but now the computer does not boot unless the USB drive is plugged in. If it's not, then when the computer boots, the boot sequence screen just appears and if I select the hard drive, it will just reboot and go back to this boot sequence screen, until I plug in the USB drive.  Any ideas? Thanks a lot for your help!  UPDATE: Having some valuable data on the machine, I would prefer a solution that doesn't involve reinstalling, but from the first replies, I guess this may be what I have to do eventually. Thanks!  GM  ==  EDIT: output of sudo fdisk -l below  Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x000742dc     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048  1449474047   724736000   83  Linux /dev/sda2      1449476094  1465147391     7835649    5  Extended Partition 2 does not start on physical sector boundary. /dev/sda5      1449476096  1465147391     7835648   82  Linux swap / Solaris  Disk /dev/sdb: 4009 MB, 4009754624 bytes 255 heads, 63 sectors/track, 487 cylinders, total 7831552 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc3072e18     Device Boot      Start         End      Blocks   Id  System         /dev/sdb1   *        8064     7831551     3911744    b  W95 FAT32   ==  EDIT2 bootinfo output:
I had Ubuntu 12.04 Beta installed on my computer. When 12.04 was finally released, I made a bootable USB Flash Drive using Startup Disk Creator.  Then I decided to check if this drive works properly and to reinstall the system on my desktop. I must add, my desktop behaves a bit strange when it comes to bootable USB's, it recognizes them as HDD.  In BIOS I changed priority of boot so USB Flash Drive (recognized as HDD) was first. Successfully booted, I installed Ubuntu. Everything worked fine, but...  Now I cannot boot from my real HDD. Every time I want to boot, I put the USB Flash Drive into my computer, boot, safely remove it and everything works.  What do I need to do to repair boot?
What exactly is "base ISO" and how do I find what is base ISO on my camera? If I understood correctly, base ISO is in full stop steps from the lowest possible ISO setting on my camera. For example if the lowest setting on my camera is ISO 100, than the following table would be base ISO:    100, 200, 400, 800, 1600, 3200, 6400   While steps in between like   125, 160, 250, 320, 500, 640, 1000, 1300, 2000, 2500, 4000, 5000   would be third-stop "pulled" values, which result more noise than perhaps higher base ISO values (for example 2500 is worse than 3200).   Did I get this right or missed by a mile, what did I miss? Do non-base ISO values generate more noise than next higher base-value ISO stop? How do I find what are my base-value ISO stops (is it the lowest ISO value multiplied by 2n)? How do I solve the partial differential equaiton  $u_{t} = (u_{x})^{-1}$  subject to the conditions $u(t,x) \geq 0$ and $u(0,0) = $0. Use the separation Ansatz $u(t,x) = f(t)g(x)$.  The inverse in confusing me The classic example... $X \sim Po\left (\lambda\right ), Y \sim Po\left (\mu\right)$, X and Y are independent.  Show that the conditional distribution of X is binomially distributed. Or in other words, $P(X=k\mid X+Y = n) = P (\tilde{X} = k), \tilde{X} \sim B\left (n ,\frac{\lambda}{\lambda + \mu}\right )$.   I've so far managed to reach to this step, and have been stuck since. Just somehow gotta get a $\frac{1}{n!}$ in the denominator, that would then complete the proof..or at least I think..  $$P(X=k\mid X+Y=n) = \frac{\frac{\lambda^{k}\mu^{n-k}}{k!(n-k)!}}{P(X+Y = n)}=  \frac{\frac{\lambda^{k}\mu^{n-k}}{k!(n-k)!}}{\sum_{i=1}^{n} \frac{\lambda^{i}\mu^{n-i}}{i!(n-i)!}}$$  Thanks for the help! I'm trying to transition from a list of pros to a list of cons, and would like to have some sort of transition quote. Something in the form of,  "But, alas, (((something something quote quote)))"  Everything that has a beginning has an end, something along the lines of that. What does the Canonical Commutation Relation (CCR) tell me about the overlap between Position and Momentum bases? C program to convert Fahrenheit to Celsius always prints zero Regex to get string between curly braces How to remove URI encoding from file names? I realise this might be quite a simple question, but I'm still quite new to the command line and only have a grasp of basic commands.  I've downloaded some lecture presentations (~25 or so) from my University however on doing so they've been named things like...  L2%20Development%20of%20immune%20system.pptx L4%20Molecular%20Recognition.pdf   As you can see they've downloaded with the URL encoding %20 instead of a space.  My question is how to batch rename all of these files so that the %20 is removed and replaced with a space instead? 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How does CoffeeScript's existential operator work? is there any uncertainty on the free particle with a definite momentum $\vec p$? The probability amplitude for a free particle with momentum $\ p$ and energy $E$ is the complex wave function: $$\psi_{(\vec x , t)}=e^{i(\vec k\cdot \vec x -\omega t)}$$  is there any uncertainty on the free particle with a definite momentum $\vec p$!? Combine the first two commits of a Git repository? Suppose you have a history containing the three commits A, B and C:  A-B-C   I would like to combine the two commits A and B to one commit AB:  AB-C   I tried  git rebase -i A   which opens up my editor with the following contents:  pick e97a17b B pick asd314f C   I change this to  squash e97a17b B pick asd314f C   Then Git 1.6.0.4 says:  Cannot 'squash' without a previous commit   Is there a way or is this just impossible? Intuitive explanation for density of transformed variable? Suppose $X$ is a random variable with pdf $f_X(x)$. Then the random variable $Y=X^2$ has the pdf   $$f_Y(y)=\begin{cases}\frac{1}{2\sqrt{y}}\left(f_X(\sqrt{y})+f_X(-\sqrt{y})\right) &amp; y \ge 0 \\ 0 &amp; y \lt 0\end{cases}$$   I understand the calculus behind this. But I'm trying to think of a way to explain it to someone who doesn't know calculus. In particular, I'm trying to explain why the factor $\frac{1}{\sqrt{y}}$ appears out front. I'll take a stab at it:  Suppose $X$ has a Gaussian distribution. Almost all the weight of its pdf is between the values, say, $-3$ and $3.$ But that maps to 0 to 9 for $Y$. So, the heavy weight in the pdf for $X$ has been extended across a wider range of values in the transformation to $Y$. Thus, for $f_Y(y)$ to be a true pdf the extra heavy weight must be downweighted by the multiplicative factor $\frac{1}{\sqrt{y}}$  How does that sound?  If anyone can provide a better explanation of their own or link to one in a document or textbook I'd greatly appreciate it. I find this variable transformation example in several intro mathematical probability/stats books. But I never find an intuitive explanation with it :( Mark my own question as favorite? If $a,b,c$ are positive integers,and $\cfrac{a}{b}+\cfrac{b}{c}+\cfrac{c}{a}$ and $\cfrac{b}{a}+\cfrac{c}{b}+\cfrac{a}{c}$ are integers then $a=b=c$ How to install program to all user accounts in Windows? I have several accounts on my home PC. I want to install a program for all user accounts, not just the one I used to perform the installation. How do I go about doing this?  I installed a program from an admin account, but it doesn't show up in the other local accounts.  I was not able to find any documentation on how to do this.  I have Windows 8.1, if that matters.