Having a similar problem here, I have narrowed it down somewhat to the fact that when you insert a copy protected game CD (doesnt happen every time) or occasionally a DVD, the whole system locks up in the manner you say. The only way around it is to reboot the PC.
This is one reason why I wont at present commit myself to purchasing this software
I did email Slysoft regarding this issue, but never received a reply, maybe because Im not registered yet?
I have recently installed 220.127.116.11 and the same problem occurs
FYI I do have a Nforce 2 board (Jetway Kocab 19P) but I use the microsoft IDE drivers, rather than the Nvidia drivers.