Last night Jedi Academy started acting funny. When playing a sound, the sound would start repeating, and the screen would freeze. Usually, after a few seconds, this would correct itself, but a couple of times, the graphics would get distorted (even after exiting the game), and only a reboot would fix them.
As time went by, this got worse and worse. Eventually I ran through several of our games, and all of them that used advanced 3D graphics had the same problem. Some would freeze and stutter often (Dungeon Seige), a few would show the graphics problem right away (Jedi Knight II: Jedi Outcast; Star Trek Voyager Elite Force), and a few would work for a while (Jedi Knight: Jedi Academy).
In addition to testing, I reinstalled the video drivers, sound drivers, and DirectX. The operating system is behaving just fine, and we're up-to-date on virus definitions and doing nightly scans. The problem seems to occur only with stuff that uses high-end 3D rendering, but isn’t confined merely to openGL, as far as I can tell. The DirectX diagnostics all ran perfectly.
Other than losing the ability to play our favorite games on that machine, this has triggered abnormally high levels of anxiety for me.
I suspect our video card has developed a problem, but am welcome to alternative suggestions.