Happening on 2 machines pretty much at same time. One is Asus Notebook with a Mobile Core 2 Duo, 2 gigs of ram, other is Desktop Core 2 Duo, 2 gigs of ram. Notebook has nvidia 8600 mobile, desktop has 2 ATi Radeon X1900s. After the computers sit idle for a while, I will come back and the desktop will be unresponsive except the mouse will still move. I cant click on any icons and the task bar wont move. I found that I could unfreeze it by hitting ctrl-alt-del and bringing up the task manager, that seemed to bring things back to normal. The displays did turn off after 10min, which I've changed to never now, and the computers never go to sleep.