Howdi all,

This is my first real attempt at joining the Linux community and it would appear after just one short day I have knacked my computer.
I am working as a Nuclear Physicist application developing a Monte Carlo Code, I have previously been using Cygwin in windows as my UNIX environment but thought now was the time to become a big boy and start using Linux (plus I have a server at work and can access it using an ssh command to run particularly challenging code).
any who..... I installed a 32bit copy of 9.04 Jaunty (because it was lying around on a disk) and it was running ok(ish) (the screen cracked up abit when Ubuntu was loading, but it was fine once it got going), I even managed to get my wireless working, and installed all the packages, compiler ect ect ect I need to write, compile, and run my MC models and have all the visualisations working and stuff (I must say I was pretty chuffed)..... I then restarted my computer feeling pretty content with myself and it hasnt worked since, GRUB now contains 3 different UBUNTU options aswell as there safe mode's (or whatever its called), the MEMTEST thinggys and XP (rather long list now).... whichever UBUNTU I choose it looks asthough its loading (the bar fills up below the word ubuntu) then the screen just cracks up (loads of blocks of random colours).....

Im hoping someone can tell me there is a real easy way of fixing this (although I doubt it)

I have been reading around and it would appear there is an issue with ATI Radeon Xpress 200M graphics cards and Jaunty and Im guessing I will need to delete Ubuntu, unpartition my hard drive, remove GRUB, then install another copy of Ubuntu ?? just wondered if anyone can advise me on the easiest way to do this, and once its done what's my best option in terms of UBUNTU release to install ??

gratitute in advance and apologies on the life story.......