I would try upgrading your graphics drivers:
Intel 82865G Graphics
Intel 865G Drivers
IF you have any problems with those drivers...
You might want to take a system snapshot so that if you have any problems, you can hit F8 at startup (before the Windows XP logo appears) and choose
Last Known Good Configuration.
If you don't take a system snapshot, you may still be able to boot up into
Safe Mode and roll back to the last version of that driver (assuming you have Windows XP set up like this -- it is by default).