A security feature in Windows Vista is Data Execution Prevention (DEP). DEP will monitor Windows services and programs and protect harmful code from executing or running in system memory locations reserved for Windows and other programs. Once DEP realizes an attack is in progress, it will shut the program or service automatically and notify you.
By default, DEP will only protect Windows and not other programs. You will have greater security protection by enabling DEP on all programs and services. If you have a program or service that doesn’t play nicely with DEP, you can turn DEP off for that particular service.
Follow these steps to turn DEP on for all Windows programs and services.