Help! System locks up randomly, corrupts CMOS in process.

[asstastic]

At random times OSX will lock up and become completely unresponsive without displaying any error messages. After a hard reboot my laptop will not turn back on unless the CMOS is cleared. I have also noticed that a small rectangle of pixels (about 5x7) in the upper left corner of the screen turns black.

 

The issue has been persistent through several versions (10.6.8-10.7.3) of OSX with a variety of system patches, power management options and DSDT edits. Any suggestions for a solution or logging and isolating the problem would be greatly appreciated.