1. Unplug your pc from the wall.
2. Press start to discharge capacitors.
3. Remove side cover.
4. Use hair dryer on cool setting to blow out dust bunnies - do not touch dryer to pc unless you are physically holding on to the case with your free hand.
5. Remove all ram sticks (hold on to case with free hand) and repeat hair dryer.
6. Reinstall all ram.
7. Reboot (before putting on side cover) and check operation.
8. If satisfactory, shut down, unplug, press start to discharge, reinstall side cover, reboot.
If that doesn't work, let us know.