Data Execution Prevention (DEP) is a valuable feature available to Windows XP users with at least service pack level 2 installed.
Since not all software and hardware fully support DEP, it can often be the cause of certain system issues and error messages.
For example, the ntdll.dll error is sometimes seen if explorer.exe, a vital Windows process, has difficulties working with DEP. This seems to be an issue with some AMD brand processors.
Follow the simple steps below disable DEP for explorer.exe.
Click on Start and then Control Panel.
Click on the Performance and Maintenance link.
Note: If you're viewing the Classic View of Control Panel, double-click on the System icon and skip to Step 4.
Under the or pick a Control Panel icon section, click on the System link.
In the System Properties window, click on the Advanced tab.
Click on the Settings button in the Performance area of the Advanced tab.
Note: This is the first Settings button.
In the Performance Options window that appears, click on the Data Execution Prevention tab.
Note: Only Windows XP users with service pack level 2 or higher will see this tab.
In the Data Execution Prevention tab, choose the Turn on DEP for all programs and services except those I select: radio button.
Click on the Add... button.
In the resulting Open dialog box, navigate to the C:\Windows directory, or whatever directory Windows XP is installed in on your system, and click on the explorer.exe file from the list.
Note: You will probably need to scroll through a number of folders before reaching the list of files. Explorer.exe should be listed as one of the first few files in the alphabetical list.
Click the Open button and then click OK to the resulting Data Execution Prevention warning that pops up.
Back on the Data Execution Prevention tab in the Performance Options window, you should now see Windows Explorer in the list, next to a checked checkbox.
Click OK at the bottom of the Performance Options window.
Click OK when the System Control Panel Applet window appears warning you that your changes require a restart of your computer.
After your computer restarts, test your system to see if disabling Data Execution Prevention for explorer.exe resolved your issue.
If disabling DEP for explorer.exe did not solve your problem, return the DEP settings to normal by repeating the steps above but in Step 7, choose Turn on DEP for essential Windows programs and services only radio button.