I'll post the next halt messages I see. The computer crashes without rhyme or reason, in Firefox, in Opera, in Notepad, in Wordpad. About the only thing I can do 100% safely is play Freecell. Or play dead. I have tested the memory successfully with Memtest86 on a number of occasions. I have done exhaustive (non-destructive) HDD tests without error. I have reinstalled Windows XP SP2 several times and Ghosted the HDD times without number. Last week, I installed a new Codegen 400w ATX P/S, which I felt sure would fix the problem. But I've had half-a-dozen BSODs since then, so the P/S wasn't the problem. I usually set the video at 800x600x32. I think it is the ATI Radeon 9200 driver, 188.8.131.5253, or the Catalyst 5.7 driver. ATI doesn't respond to my emailed request for support, so here I am!