Unbuntu graphics problem

[pinkyshot]

I just installed unbuntu 8.04 and I am having problems with it. First I tryed to set it up with the option it had to install next to windows and it totally messed everything up I could get on to ubuntu, but the screen is all messed up it has crackly lines running through it, and its hard to see what I am doing. It also made it were I could not get on to XP, it said I was missing some files. So I had to do a complete reinstall of windows. Then after I got windows up and running again I tryed to see if I could get it to work with the option of running it in windows. Which seem to work, since I can still get on to windows which seems to be working fine, but I am still getting the crackly lines through the screen on Ubuntu.

I just put the this motherboard in my computer, its a ECS GOAL3+ AMD Sempron 3000+ 754 SiS 761 GX Micro ATX Motherboard/CPU Combo. So its not like I have a old motherboard. I also have 1 gb ram installed with one 100 gb hard drive as master and 250 gb as slave.

I was just wondering if there was anything I can do to fix this, maybe some upgrade, or configuration. This is my first time with unbuntu, so I am still not very familiar with it. I see a lot of people have had cases with a bad burn, but besides the screen problem everything else seems to be working fine. I am even using it right now to write this.

I hope I gave enough information to help me out with this problem...If anyone can help thank you! :confused:

[macaholic]

What graphics card do you have?