To read about what DEP does and how to change its settings, click Start on your Vista taskbar, then click Help and Support. In the "Search Help" field at the top of the help window, type "dep" and press the Enter key on your keyboard. You should see several entries related to DEP, which you can browse to become familiar with this Vista feature. To change DEP settings, click on "Change Data Execution Prevention settings." Depending upon how Vista is set up on your computer, you may see that DEP is turned on for all programs. If this is the case, you can choose to either set DEP only for essential Windows programs and services, or to disable DEP for the game only by follow the instructions for turning off DEP for an individual program.