Originally Posted by Slaymate
You don't want to run Prime95 for a HD6950 problem. You want to run Furmark
to test the gpu and try using HWMonitor
to view your temperatures, voltages and fan speeds.
Strangely, you didn't read everything. His computer is hard locking, not just graphically, but all over. So it isn't a graphical issue that is the root cause most likely. One thing unique to his system, two processors, chances are his chipset drivers are not updated, or something is causing a fatal error. Event viewer and stressing other parts of the system would be of benefit. Also note, he isn't having this issue when he just ran furmark, which further proves my statement.