Due to the way Windows Vista's boot editor has been created, it is now harder to disable DEP / No Execute Protection. However, after some amount of research, it would seem that some of the random Windows Explorer crashes that users are experiencing is caused by this technology. You will need to disable it and reboot, which should cure some of the crashes:

   1. Click Start, All Programs, Accessories, right click on "Command Prompt", and click "Run as administrator".
   2. If asked for permission to run Windows Command Processor, click on Allow.
   3. At the command prompt, type in "bcdedit.exe /set {current} nx AlwaysOff" (without the quotes).
   4. You should receive a message saying "Operation Completed Successfully".
   5. Restart the computer, DEP / No Execute should now be disabled.

cheers!!!