1) Check your car wiring job. Use alternate wiring if you are unable to find the problem... Avoid using your cigarrete lightler as a power source., it is not reliable.
2) Make sure your M/B does not overheat. (not the PSU -- M1-ATX can go as high as 105 Celsis).
3) Avoid ground loops -- keep the PC chassis as much as possible away from the car chassis. In most situations you should be OK, but you never know...
Originally Posted by Montanaja