It's probably not a virus. I've seen it before at home and out in the field.
You've got a blown graphics card and the situation is deteriorating. Best
case scenario is that it's just the driver in which case boot into safe mode
otherwise try and pop a new card. If you're unsure, see if you could borrow
a working card from somebody and see if the problem is resolved. This way,
you'll know out right if it's the card that's causing you problems. If
you've tried both, then try a virus scanner, provided you could still boot
in.
Otherwise, try this trick. You'll need a friend with a computer that's got
an up-to-date virus scanner. Pop the drive out and jumper it so that it's a
slave. Pop the drive into your buddies computer and boot in. Before you even
try to see the drive in explorer or such, start up the scanner and ensure
that it's scanning all files (not your "smart scan" BS) and scan your drive
(which is the slave). If it's find something, nuke anything that the scan
finds (you don't have much choice) and pray that your drive will boot back
in later. If it doesn't find anything, then the O/S is screwed. In which
case, just try and load the O/S over the top of it and see if you could
recover that way.
If not, then pop the drive but into your buddies' system and yank anything
of use off the drive, you're only option may be to format the drive as
either a system file is cactus or the drive has bad sectors and it's
starting to go.
Good luck.
All the best,
Ka.