You will need to set up a test scenario, e.g build a set of tests upon which always will produce a same type of error,
then while keeping a track on which component might contribute to the error.
All the above tests shall pass/complete without errors.
Keep an eye on the CPU temp, motherboard temp, GPU temp, Voltages.
Compare results while using onboard VGA and the 8400.
Use one and two sticks of RAM.
If the temps are OK, would focus on the RAM, VGA and the Power Supply.
Then lastly, using the latest recommended drivers for that OS for all components in the system.
If all else fail,s might try to update the BIOS, if your board now has the oldest BIOS. Note however the risk with that, do not use LiveUpdate. A failed BIOS flash may ruin your board.
12:41 AM by