Hi...
Here i am going to discuss the best way to install ubnutu in your PC without affecting your windows partition......

Let's Discuss about ubuntu ultimate edition 2.1

1. Change your boot options to 'boot from cd/dvd as primary.
2. Insert the ubuntu ultimate 2.1 Disk to drive and reboot...
3. Choose install and you will get the gnome screen for installation.
4. Click on install.
5 .Now der are 7 steps for ubuntu installation in ubuntu ultimate 2.1 edition installation...
7 .Now complete those steps to complete installation....


FOR XP and VISTA users:

To get the maximum efficiency of ubuntu ultimate edition you have to install ubuntu in a seperate drive....If you choose install inside windows, there will be much problems..mainly disk space issues.....


MANY FEAR THAT THEY WILL NOT BE ABLE TO ACCESS THEIR WINDOWS OS IF YOU INSTALL UBUNTU IN A SEPARATE PARTITION

First calculate the disk space that you need to allot for ubuntu installation..A minimum of 20 GB will do.........If you don't have a drive of say 20GB space then make it in windows using some softwares like magic partition..U can do the same using ubuntu setup manager but as You have already installed windows that will be the best option...

Now in the ubuntu installation in the partition editor give this drive for installation...
change filesystem to ext3 and mark format...
DO NOT FORGET TO SELECT THE ROOT'/' IN THE INSTALLATION DRIVE....
Now proceed and you will have ubuntu ultimate 2.1 installed in your system...
When you restart you will get the grub boot loader will will help you to switch os.