I want to install a new Ubuntu on a drive where a previous Ubuntu system is already installed beside Windows7.  The first option says that only Ubuntu will be replaced.   The second says that all will be erased.  I only want Ubuntu replaced with the  new one while keeping Windows7 untouched.  Is the first option (“Erase Ubuntu16.10 and reinstall”) the good one in this case?
I am trying to install a fresh version of Ubuntu in my computer without touching the windows 10 dual boot! In the Installation Type, the first option seems exactly what i wanted to do.  My question is, is this feature is safe to use? because i don't want to lose any windows files and other NTFS partitions on the hard-disk. Please eliminate my confusion. Note as that i dont need any files or media which are in the ubuntu partition, Thanks.
After burning Ubuntu 12.04 to a CD, I tried booting and got the message:  This kernel requires the following features not present on the CPU: pae  Unable to boot - please use a kernel appropriate for your CPU.   What does this mean? I had Windows 7 and Ubuntu installed on the same partition   Some time later, decided to uninstall Ubuntu.So I booted Ubuntu,Changed the hd related to it to NTFS,I did NOT extended my main drive   restarted-> GRUB rescue&gt;. No surprise since I had just wiped out the whole GRUB directory staff   Now I just want to boot into my windows.Move my necessary files to an external memory and reinstall the windows seven     What I have in my hands: Ubuntu live CD, A copy of win7 DVD I tried to make use of the win7 DVD(I had lost my DVD) to fix the mbr but the problem is when I choose repair, It says that this version of Windows is incompatible with yours What should I do? Topological/Geometrical justification for $\text{CFT}_2$ being special It is known as a fact that conformal maps on $\mathbb{R}^n \rightarrow \mathbb{R}^n$ for $n&gt;2$ are rotations, dilations, translations, and special transformations while conformal maps for $n=2$ are from a much wider class of maps, holomorphic/antiholomorphic maps. I was wondering to know if there is any topological or geometrical description for this.   To show what I mean, consider this example: in $\mathbb{R}^n$ for $n&gt;2$ interchanging particles can only change the wave function to itself or its minus. It is related to the fundamental group of $\mathbb{R}^n-x_0$ ($x_0$ is a point in $\mathbb{R}^n$ and $\pi_1(\mathbb{R}^n-\{x_0\})=e$ for $n&gt;2$) but this is not true for $n=2$.   I want to know whether exists any topological invariant or just any geometrical explanation that is related to the fact that I mentioned about conformal maps on $\mathbb{R}^n$. The question is :   Show that $I=\langle 2+2 i\rangle$ is not a prime ideal of $\mathbb Z[i]$. Also find the number of elements in $\mathbb Z[i]/I$ and its characteristic.  My try:  I started with elements $2, 1+i \in \mathbb Z[i]$. Clearly, the product is $0$ in the coset representation.  The part where i am struck at is the number of elements and the characteristic.  Well, $2+2i+\langle 2+2i\rangle=0+\langle 2+2i\rangle$  Can we directly write $i^2=-1$ in the coset representation? Which damage dice exactly does the Great Weapon Fighting fighting style allow you to reroll? In the context of topological spaces, I see the following major countability properties:  A space is:   "separable" iff it has a countable dense subset "second countable" iff if has a countable basis "first countable" iff the neighbourhood system of every point has a countable local basis.   (Definitions taken from Counterexamples in Topology by Steen and Seebach, 2nd ed. 1978 -- there may be differences in wording from other sources.)  The question I have is: "separable" into what, exactly? By which I mean to say: what is the thinking behind calling such a condition "separable"?  It appears not to be related to the concept of "separation axioms", which do immediately and obviously invoke an intuitive notation of separation, neither does it seem to have anything to do with "separated sets".  (Anyone using the spelling "seperable" or "seperated" will be immediately downvoted. :-) ) system() has been disabled error message Is my phone liable to explode if I charge it with a charger that came with a different phone? How to refer Javascript cloud page in my email in content builder? Pass an extra argument to a callback function Which is the correct sentence?   The young cow is calf. The young cow is called calf. The young cow called as calf. How do I create an .exe for a Java program? Why every polynomial over the algebraic numbers $F$ splits over $F$? I read that if $F$ is the field of algebraic numbers over $\mathbb{Q}$, then every polynomial in $F[x]$ splits over $F$. That's awesome! Nevertheless, I don't fully understand why it is true. Can you throw some ideas about why this is true? According to my logic,  $$\large\sqrt{x^2} = x^{2\times \frac{1}{2}} = x = x^{\frac{1}{2}\times 2}={(\sqrt{x})}^2$$  But when I look at the graphs of these guys, they're totally different.  Edit: Complex answers are okay, if you know what I mean. Why do ssh operations always ask for passphrase? (with ed25519) I just updated my ssh key and added a passphrase, however it constantly nags me for it now, such as when I do a git (or mercurial hg) push.  ssh-agent is running:  xxx  1303  1118  0 09:16 ?  00:00:00 /usr/bin/ssh-agent    /usr/bin/dbus-launch --exit-with-session     /usr/bin/im-launch mate-session   I tried ssh-add:  &gt; ssh-add Identity added: /home/…/.ssh/id_rsa (/home/…/.ssh/id_rsa) Enter passphrase for /home/…/.ssh/id_ed25519:  Could not add identity "/home/…/.ssh/id_ed25519":      communication with agent failed   What is missing?  16.04 Ubuntu Mate, in case it matters. How to debug hadoop mapreduce jobs from eclipse? I'm doing a bit of self study, but I'm uncomfortable with a certain idea. I want to show that $f(z)$ is analytic if and only if $\overline{f(\bar{z})}$ is analytic, and by analytic I mean differentiable at each point. Here $f$ is a complex valued function.  What I do is write $f(z)=u(x,y)+iv(x,y)$, where $u$ and $v$ are real functions of two variables. Then $\overline{f(\bar{z})}=u(x,-y)-iv(x,-y)$.  These two forms look very similar, in the sense the one function being differentiable should immediately imply the other is differentiable, since the only thing really changing might be a $-$ sign popping out due to the chain rule.   How can I more rigorously express that $f(z)$ is analytic iff $\overline{f(\bar{z})}$ using this? Many thanks. Safely moving and creating new tempdb files Two things I'd like to know:   how do you safely move tempdb with minimal downtime? how many tempdb files do you need?   Is it 1 file per core? So quad-core = 4 tempdb files, creating three new ones? Why does the classical path give the dominant contribution in the path integral? irrationality of $\sqrt{2}^{\sqrt{2}}$. The fact that there exists irrational number $a,b$ such that $a^b$ is rational is proved by the law of excluded middle, but I read somewhere that irrationality of $\sqrt{2}^{\sqrt{2}}$ is proved constructively. Do you know the proof?