Hello. I am running a dual-boot with Windows XP. The Windows mode runs fine but things freeze up when I try to use Ubuntu. I have ver. 9.04.

I have tried CTRL+ALT+F2 to kill a PID but the command doesn't do anything. So I'm totally froze up. Must be a corrupt file or something. I always have to manually push in the power button to shut things down.

Can I re-install Ubuntu without re-installing Windows? Whats the best way to go about re-installing Ubuntu? When they come out with new versions of Ubuntu do they provide any kind of step by step guide for a newbie?

It is possible to upgrade Ubuntu to the next version instead of reinstalling. But if your current Ubuntu is not working properly then I would do a clean install (reinstall) of Ubuntu instead of upgrading.
Here is good guide for installing Ubuntu:
http://www.psychocats.net/ubuntu/installing
And for creating a separate home partition during the install:
http://www.psychocats.net/ubuntu/installseparatehome
That psychocats site is a very good beginners resource for Ubuntu.
You will not have to reinstall Windows when you reinstall Ubuntu. Just reinstall Ubuntu to the same partition that it is currently installed on.
I assume that you installed Ubuntu to a dedicated linux partition on the hard drive. Is that correct, or did you install Ubuntu inside Windows with Wubi?

Thanks for the help. I have a seperate linux partion, not Wubi.