If you have an application that doesn't adhere to the DEP code of behavior, you'll encounter a Data Execution Prevention warningWorking with DEP exceptions
As I mentioned earlier, hardware-enforced DEP is not enabled in Windows XP SP2 by default because it would often prevent legitimate legacy programs that don't adhere to the DEP code of behavior from running, thus giving the impression that the security features in SP2 would break applications. Apparently there are a lot of legacy programs that don't adhere to the DEP code of behavior.
As such, after enabling hardware-enforced DEP from the Data Execution Prevention tab, you may indeed encounter a problem between DEP and a legacy program. If you do, you'll encounter a Data Execution Prevention warning dialog box, like the one shown here.
Greg Shultz is a freelance Technical Writer. Previously, he has worked as Documentation Specialist in the software industry, a Technical Support Specialist in educational industry, and a Technical Journalist in the computer publishing industry.