Missing keys when typing and Motherboard failure

It very well could be. But it does sound more like a power issue to me, what kind of hardware are you running and what PSU do you have? If you're running 500w worth of gear on a 500w power supply, you may just be pulling too much wattage causing low power to the entire system.

I'd start by unplugging some stuff in the system to see if it still occurs. Things like extra hard disks, USB devices, and even if you can pull out some expansion cards. If the thing still acts up; it may simply be a motherboard failure.