First of all. I've assembled new system:
Intel D915GAV/P4 3,0 GHz HT/256 DDR Kingston x2/Maxtor SATA 120 Gb/300W Power Master
Installed XP Prof SP2 - everything worked just fine, while I've been using onboard video.
But then i've installed Sapphire Radeon X600 (PCI-E, of course) and here this nightmare begins. System hangs up when you don't do anything - just brousing HDD, or work with text documents, or something like that. If "VPU recover" is on, crashes occur every minute, really! VPU recover recovers it and offers to reboot, but after reboot everything happens again. If "VPU recover" is off, system is a little bit more stable, but freezes completely, if crash occurs.
The funny part is that system works just fine in 3D!!! If you'll manage to launch 3D game - you can play for hours without single crash!!!
Bad thing is I've never tried to put this accelerator in another system, so I cannot say is this just an internal damage of video card, or something else.
And I think it's not because of 300w power supply - because everything works fine in 3D. :-\