Windows XP Service Pack 2 (SP2) have implemented function to protect your computer from malicious software code into areas of memory which is reserved for unexecutable code by integrating hardware and software technologies named Data Execution Prevention (DEP). Hardware DEP is a feature of CPU that keep the execution of code in memory areas that are fixed for storing a data.

If you have Windows XP with SP2, you can stop this kind of attacks by software method. I say "software", because also have a hardware method like we already explained.

Data Execution Prevention (DEP) is a new technology already implemented in SP2 for Windows XP and this feature can be turned off, but default stated is turned on for some system applications and services. Now we will tune up and do some tweaks.

Go to My Computer > Properties > Advanced > Performance > Settings > Data Execution Prevention and select Turn on DEP for all programs and services except those I select.

Of course you can select some programs which you don't want to use DEP protection. To set list with this application click on Add button and select desired applications from Browse window. Now click on OK button.

When ready with setup of DEP you can check the functionality of DEP with some test program.

NXTEST is an software program which gives you ability to check that Data Execution Prevention (DEP) is active on your computer by trying to execute code from a data area, the process heap and the program stack, and reports whether all attempts were prevented by the operating system or not.