Bad News:
MCE's are always hardware related errors.
These exceptions are triggered when the processor finds hardware malfunctions such as TLB, bus or other unrecoverable hardware failures.
They can be caused by b0rked motherboard or gfx-card components, but most frequently are related to some of the below causes:
- Bad RAM modules
- Overstressed or deficient power supply
- Improperly configured components
- Extreme thermal conditions
You can check point 1 using
memtest, a utility which runs from a liveCD. Most modern distro's LiveCD has this option. Try Knoppix. Also test if the modules are properly attached to the mainboard. The definitive solution is obviously replacing the modules.
Regarding to point 2; check that your power supply runs smoothly w/o noises or vibrations, check the connections and try to ensure that the amount of power used by your devices aren't higher as the nominal power of the supply. If you don't feel like doing the math, try disconnecting devices, such as CDROM/DVDs, USB devices, etc. A solution is getting a more powerful supply.
Point 3 includes overclocking of the bus or the CPU. I can't stat if it also affects GPU but I'm almost sure it does. Set your components to the vendor rated settings.
Point 4 is mostly related to cooling device malfunction, check the fans and replace the ones which doesn't behave properly (vibration, excess noise or simply not running at all). You can also try to boot after letting the system rest for a time so that it cools and check the temperature using your OS's sensor software.
I unfortunately don't know the exact translation of the MCE codes, perhaps they are documented in the specs of your processor, but IMHO the above checklist will be enough to find the culprit.