I have observed that very often I'm getting the message "DATA EXECUTION PREVENTION To help protect your computer, windows has closed this program. Name:Windows Explorer". I get this message when I use windows explorer to browse the files. After I select the message close this message windows explorer crashes or the windows explorer window closes and I get a message Windows Explorer has encountered a problem and needs to close. It doesnt allow me to browse through the files in Windows Explorer. This happens more often when I'm checking folders which have AVI files in them and also when I try to open AVI files with Windows Media Player Classic, the media player window opens for few seconds and then closes. I'm not able to play AVI files in Windows Media Player. I had run several Antivirus programs and also formatted my HDD but it worked for few days but again its giving the same problem Even after I select the option dont use DEP for following programs and selected Windows Explorer still the problem persists. Please help!