Having a weird issue with x1300

I am having a strange issue with My Diamond x1300SB 256mb AGP video card. When I play World of Warcraft, the game sporadically minimizes to the desktop, as if I were pressing Alt+Tab...but I'm not.

I am using the newest Catalyst drivers for this card, version 7.1. My system is a Dell 4600, 2.4ghz Pentium 4, 1.5GB RAM, 40 GB Hardrive, Soundblaster Live! 5.1 sound card, stock 250W PSU (everyone will try to blame the PSU, but that isn't the problem), not sure about the motherboard. However, I do know that I have the most updated BIOS from Dell, A12 I believe.

I'm not using any third-party tweak programs, just the Catalyst Control Center. If anyone else has experienced this with any x1X00 series card, please share any input and/or fixes you have or know about. Thanks!

-ledzep