How to edit partition of Ubuntu 10.10-Windows vista ?

Did you install Ubuntu in the standard way, by starting up your computer from the Ubuntu installation CD and installing Ubuntu *alongside* Windows, or did you install Ubuntu *inside* Windows, with Wubi?

I installed Ubuntu *alongside* from a CD

In that case, assuming you installed Ubuntu to the same physical hard disk as your Windows system, you'll have to shrink down the Windows partition (which is probably the largest partition of type NTFS), and then expand the partition containing the Ubuntu system's root filesystem (which is probably the only partition of type ext4). You can use GParted on the Ubuntu Desktop Install CD to accomplish this. To do that, boot from the CD, select Try Ubuntu, and go to System > Administration > GParted Partition Editor.

After you shrink down the Windows partition, expand the ext4 partition to the left, so it takes up all the available space. If the ext4 partition is contained within an "extended partition" and the Windows partition is not, then you'll have to first expand the extended partition to the left, so it takes up all the newly available space, and then expand the ext4 partition to take up all the newly created space within the newly expanded extended partition.

The way GParted works is that you specify the changes you want to make (or some of them), and then you click the green check mark to apply them. Until you have clicked that green check mark, the changes are not actually applied. Be very careful when using GParted, because you can easily destroy data with it by accident. In fact, even if you were an expert user of GParted, dynamic partition resizing is still somewhat risky business. While usually no data loss occurs, the risk of it occurring is high enough that you should first back up any important files--e.g. your documents--from *both* your Windows system *and* your Ubuntu system. (Needless to say, backing up the files from one system by creating copies of them in the other system is *not* an adequate way to back them up, since the data in *both* systems is put at risk by this process.)

After you do back up your data and, using GParted, shrink the Windows partition and expand Ubuntu's ext4 partition, once you've booted back into your Ubuntu system (after rebooting the computer using the power icon on the upper-right corner of the screen, make sure to take out the CD so that it doesn't inadvertently boot from the live CD again), it's a good idea to open a Terminal window (Applications > Accessories > Terminal, or Ctrl+Alt+T) and run the command:

sudo update-grub

To run a command, paste it into the Terminal, or type it in exactly, and press enter. You may be prompted for your password. If so, type it in and press enter (and don't worry about how no placeholder characters like * appear).