I think for the most part, electronics either work or they don't. It is rare that your video card has a hardware malfunction and can still operate at the same time.
For the most part, your problems are associated with software.
i.e.
outdated hardware w/ outdated drivers trying to run current software
current hardware trying to run out of date software
operating system software issues affecting software
generic driver issues
etc...
TO make sure it is a problem not associated w/ UT99, try playing different games to see if similar things happen. If so, you may want to back up your important info and do a clean install or run virus scan/spyware removal