Comment 20 for bug 1228109

I believe I had the same issue, my M91p would freeze after some random time from boot, however its not an immediate hang, the mouse cursor goes on a go slow, then disappears over a few seconds, keyboard and mouse are then totally unresponsive including ctrl-alt-f1 etc. However I *think* its just the UI thats locked.
I've done 2 things which appear to have resolved my problem (yeah I know bad practice, one change at a time) installed the latest proprietary nvidia driver (I have the NVS 300 card) I assume you all do too. And I set the BIOS video selection to PEG (pci express graphics?) rather than auto. I know I had to do something similar with my dual card Lenovo W520 laptop with similar symptoms.
Can you confirm if this is the same problem and if this works for you?