Originally, I was having problems resuming from sleep mode, which was solved by disabling the AlienFusion service. However, when I leave the computer on for a while and am not using it, sometimes when I come back to it, it will have locked up in the same way it did when failing to resume from sleep mode. It is not set to automatically go to sleep or hibernate. The screen goes blank, and it is unresponsive. The internal fan still cycles, the lights stay on, but it can do nothing other than turn off.