I upgraded system from PIII to P4 using your P4SGA motherboard. The system seemed to run fine at first, but now I am getting hardware reboots. What's wrong?
If you only replaced the motherboard and not the power supply to a P4 power supply, the system may boot up, but will be very unstable because of lacking the 12V line required by P4 systems. Please replace the power supply with a P4 power supply and this should cure the problem.