this really doesnt sound like a virus - are you sure of your video connections? (connection to the monitor, the card in it's slot, etc) also, you might want to update your video driver.
I'd say you have some serious issues with hardware, either graphic card, motherboard, power supply, or some combination of all :D Think it would be wise for someone with some technical background to check it out.
I would try to boot on a CD (or some other device). If necessary, you should be able to copy any data not backed up to a USB external drive. I agree, it could be hardware that has failed. This is handy to have: For what it's worth, I am using Microsoft Security Essentials. It's free and does not get in the way as much as Norton and others seem to do. You may need to do a complete format and reinstall again. It sucks, but sometimes that is all that will work. I would run chkdsk to make sure it's the drive is ok too.
If it's not failing right off the bat, but after it's booted and been on for 5-10 mins. I'd say check the fan on your video card if it has one. Sound like it might be over heating.
OK. Just got back from work. Thanks for all of the answers. After I eat something I will open it up and reset the video card or try going back to the on board video to see if that works.