Hello, I'm new and this is my first post to the board. I've been building systems for years now but this has stumped me. I need all you geniuses to help 
I built a new system which ran fine for 2 months and then became completely unstable. Random reboots, after reboot I will lose video or get a message during POST "OC Fail, please change OC fail settings"
No new hardware has been added except a small IDE HD for use as a Linux drive. I replaced the motherboard (GA-8I915P Duo), the video card (Gigabyte Geforce 6600) and the power supply (350w that came with the case) but the problem remains. I listed everything I replaced in the list below. Everything I change seems to help for a day or two and then back to random restarts and then followed by OC fail at boot.
Here is my current system config:
3.4GHz Pentium 4 550 Prescott
MB GIGABYTE GA-8I915P DUO PRO 915P (replaced, no change)
512MB Kingston RAM DDR2 533
Western Digital 250GB 7200 RPM Serial ATA150
CHAINTECH GEFORCE6600 256MB (replaced, no change)
THERMALTAKE 420W Power Supply (replaced, no change)
Cpu temp between 34 and 38 celcius
Voltages:
+3.3V = 3.3.20
+12V = 11.850
VCoreA = 1.320
I built a new system which ran fine for 2 months and then became completely unstable. Random reboots, after reboot I will lose video or get a message during POST "OC Fail, please change OC fail settings"
No new hardware has been added except a small IDE HD for use as a Linux drive. I replaced the motherboard (GA-8I915P Duo), the video card (Gigabyte Geforce 6600) and the power supply (350w that came with the case) but the problem remains. I listed everything I replaced in the list below. Everything I change seems to help for a day or two and then back to random restarts and then followed by OC fail at boot.
Here is my current system config:
3.4GHz Pentium 4 550 Prescott
MB GIGABYTE GA-8I915P DUO PRO 915P (replaced, no change)
512MB Kingston RAM DDR2 533
Western Digital 250GB 7200 RPM Serial ATA150
CHAINTECH GEFORCE6600 256MB (replaced, no change)
THERMALTAKE 420W Power Supply (replaced, no change)
Cpu temp between 34 and 38 celcius
Voltages:
+3.3V = 3.3.20
+12V = 11.850
VCoreA = 1.320