Heat from the northbridge on Intel based boards is normal, they will get hot.
Just get down and look at the fan on the videocard make sure it's spinning. If it's been in the system for a while, turn the computer off and take the card out, clean out the dust from the heatsink and fan.
I had a video card fan go out on me at work and it would be fine in windows and all of a sudden....crash to black/blue screen with funky colors. But sometimes it'd run for an hour or so before it'd do that, finally opened up the case and saw the fan wasn't turning and Videocard heatsink was boiling hot.
Otherwise I'd say your drivers are out of date and/or games are not patched. But seeing as both games crash the same way it's probably videocard driver/heat problem.
good luck
That's what she said...