Windows 7 explorer.exe keeps crashing - ntdll.dll fault

Hi mcutting,
Welcome to Microsoft Answers!

The causes of ntdll.dll error messages can vary greatly. However, most ntdll.dll errors result from a corrupt or damaged version of the ntdll.dll file itself, corrupt hardware drivers, or issues between Windows and other programs.

NOTE: THIRD PARTY SOFTWARE DISCLAIMER
Using Third Party Software, including hardware drivers can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the use of Third Party Software can be solved. Using Third Party Software is at your own risk.
 
Method 1: Perform a clean boot
Note: If the computer is connected to a network, network policy settings may prevent you from following these steps. We strongly recommend that you do not use the System Configuration utility to modify the advanced boot options on the computer unless a Microsoft support engineer directs you to do this. Doing this may make the computer unusable.

1. Log on to the computer by using an account that has administrator rights.
2. Click Start, type msconfig.exe in the Start Search box, and then press ENTER to start the System Configuration Utility. If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
3. On the General tab, click Selective Startup, and then click to clear the Load startup items check box. (The Use Original Boot.ini check box is unavailable.)
4. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.
Note Following this step lets Microsoft services continue to run. These services include Networking, Plug and Play, Event Logging, Error Reporting, and other services. If you disable these services, you may permanently delete all restore points. Do not do this if you want to use the System Restore utility together with existing restore points.
5. Click OK, and then click Restart.

Note: Reset the computer to start as usual
After you have finished troubleshooting, follow these steps to reset the computer to start as usual:
1. Click Start, type msconfig.exe in the Start Search box, and then press ENTER.If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
2. On the General tab, click the Normal Startup option, and then click OK.
3. When you are prompted to restart the computer, click Restart.

Check out this link which talks about “How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7”
http://support.microsoft.com/default.aspx/kb/929135

Regards,
Divya R – Microsoft Support.
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