Step one to any hardware troubleshooting: Take apart all connections. Remove every cable, unplug everything. Clean out what you can (compressed air is awesome), dust the system, check cords for splits or cuts. Then hook everything back up, bit by bit, and start it up again. A loose power cord could be the cause, so could dust in the wrong spot.

Otherwise, it's probably an internal issue, and those aren't usually quick and easy fixes.