Flash your CMOS or you have a PSU issue. Sometimes the source is the PSU but you power provider could be at blame for giving you crappy juice. Make sure you use a UPS box. Otherwise get a better PSU like Enermax, Antec, or Fortron Source.
Mobile Barton 2500+ @ 2420mhz 11x220 1.7v
Asus A7N8X Dlx 440 FSB
1gb Geil GD pc3500 Dual Channel (2-3-3-6)
Segata 80gb SATA 8.5ms seek
ATI Radeon 9800 Pro(420/720)