freezing and monitor blackouts

Ok, this mostly happens with trillian, although not exclusively. I try to do something in trillian like view someone's status, the computer freezes unless I move the mouse a lot or press ctrl alt delete, and then the screen goes black for a second then comes back on with some garbled graphics sometimes. How do I fix this?

Most scary thing that happened was it locked up on the login screen and I couldn't do anything to unfreeze it. So after I turned the computer back on, there were green and brown lines going down and the graphics were totally messed up and moving around. I went to properties and for some reason it had me in 4-bit, instead of you know like 32-bit, with the lowest resolution.

Luckily, the green lines and stuff went away when I rebooted, but the only thing that's different is the font for some reason. I'm still getting these quick freezes though. And I don't want those green lines to come back. How do I fix this?

I'm using WinXP.
It says "Plug and Play Monitor on NVIDIA GeForce 256" and I think the NVIDIA thing is the graphics card.

Let me know if you need to know anything else to help me.

Do you have a secondary Graphics card you can test on(I had an onboard graphics card that went bad and was doing similar things). If you have a PCI, PCIe, or AGP card that you are currently running off switch to the monitor plug to the onboard(if you have any) and see what happens.

If you don't have any other VGA port to plug into you can try to see if something managed to corrupt your video drivers(simply reinstall the drivers).

Maybe, I emailed my brother if he had the install discs. No, I don't have any onboard graphics card I don't think.

Do you think it could also be overheating issues? It's a thin monitor that's feels very hot near the vents, unlike my computer.

Trillian :shoot:

If it crashes on one specific command, it can't be the overheat.