Screen-keyboard lock-up

I have a strange problem that seems to be related to a background 360 process. If I leave the computer for several hours, I will on occasion return to find the keyboard and mouse locked up. Typically, pressing the reset button and "starting Windows normally" will bring the system back. I have discovered that if I then go in and run all of the various 360 tasks manually, then the problem seems to go away for some period of time, usually days. If anyone has any ideas what might cause such a thing, or has suggestions for a solution to prevent this from happening, it would be most appreciated.