DEP(Data Execution Error) when we click on any file. For disabling it do the following:
If you have XP SP2,then it may be “Data Execution Prevention”(DEP)error. Turn off DEP in the XP control panel.

1.Click the start button at the bottom left of your screen.
2.Click the Control Panel menu item.
3.Then,double-click the System icon.
4.Click the Advanced tab.
5.Find the item marked performance right under there is a button that says settings.
6.Click the Data Execution Prevention tab.
7.You will see two options in that window.Click the second option that says “Turn on DEP for all programs and services except those I select
8.When you are finished with that then click the’Add…’ button it should be visible at the bottom of the box. Then,you have to find where the file ‘explorer.exe’resides on your computer most of the time it’s something like this C:\windows\explorer.exe anywayadd explorer to that list. it’ll give you a warning just ignore it and click ok. Then you reboot and if you try it everything should work just fine.