I've had this issue for about three weeks now, and DEP has been shutting down some programs (IE, AVG, etc.). After working with a tech support guy in another forum, it was determined that this issue was NOT related to malware/viral infection. I have tried options all over the internet (from enable/disable within the Advanced Security section in System to changing the BIOS to AlwaysOn and OptIn), but nothing has worked. I have managed, for unknown reasons, to get IE and the AVG Interface to work, but some secondary programs are still being shutdown. And now, the options within the Advanced Secuirty section under DEP are greyed out (I have already tried to run the command to AlwaysOn and OptIn, but it doesn't work). I'm afraid that this will issue will begin to affect other critical systems that would prevent me from doing anything on the computer. I need help to get past this. Thanks.