Reader Sue is having trouble with video files: Every time she tries to open one, Windows displays a Data Execution Protection warning, then a Dr. Watson error, and then closes the file. The files themselves aren't corrupt, she says, because they came from her digital camera and work fine on another PC.
Interestingly, Sue also notes that the problem PC is not connected to the Internet, but rather used offline strictly for A/V projects. She wants to know if it's safe to disable DEP and, if so, how to go about it.
This is a bit tricky to troubleshoot, Sue, in part because you didn't tell me which version(s) of Windows you're running and whether or not you have any security software installed. See, DEP is there to help protect your PC from viruses and other threats. It's possible that your offline machine already picked up a virus, hence the DEP warning. And because the machine is offline, you're not getting the necessary security updates for Windows or your anti-virus software (assuming you're using any).
You also didn't tell me which program you're using to open your video files. If it's something other than Windows Media Player, the program itself could be in need of updating--again a difficult task if you're not online.
Is it possible to disable DEP? Yes, though do so at your own risk. Microsoft's "Data Execution Protection" support page has the details. (It's intended for Windows XP users; I'm guessing that's your OS.)
Let me leave you (and other readers) with two thoughts. First, although keeping a PC insulated from the Internet may seem like a smart way to protect it from online threats, there's a downside as well: you don't get the software and security updates you need for protection against "offline" threats (like viruses introduced via flash drive).
Second, learn how to ask for tech help. I might have been able to solve Sue's problem (rather than just guess at it) if I'd known more about her operating system, security software, etc. The details she gave me (like how CompUSA couldn't help, even after five tries) weren't the right ones. Help me help you!