I have just got a new PC running Vista Home Premium. When I try to download an install one particular package, a message appears aying the installation has been blocked by “Data Execution Prevention”. What does this mean?

Data Execution Prevention (DEP) is a security feature that protects your computer from malicious software. You could turn it off in XP, but not on Vista. The best thing to do is to contact the provider of the software package you’re trying to run and see if they can help you. Here’s some more information from Microsoft’s website:

The primary benefit of DEP is to help prevent code execution from data pages. Typically, code is not executed from the default heap and the stack. Hardware-enforced DEP detects code that is running from these locations and raises an exception when execution occurs. Software-enforced DEP can help prevent malicious code from taking advantage of exception-handling mechanisms in Windows.

It is for your protection after all, much like a pair of Dansko boots protect you when stamping on rocks.