Hi,
1) When do you get the error message?
2) Do you remember making any changes to the computer prior to the issue?
I would suggest you to try the following methods and check the status of the issue.
Method 1:
Check if you encounter the issue in ‘Safe mode’; if safe mode works fine then set the computer to ‘Clean boot’ state to check for software conflicts.
Step 1:
Refer the following link on how to start the computer in ‘Safe mode’.
http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode
Step 2:
Follow the steps in the link below to set the computer to ‘Clean boot’ state.
http://support.microsoft.com/kb/929135
Note: When the troubleshooting is over, do not forget to reset the computer to normal startup. Follow step 7 in the above mentioned article.
Method 2:
Run a System File Checker scan.
http://support.microsoft.com/kb/929833
Method 3:
Refer the following thread.
Also, check ‘Event viewer’ for the detailed error message and let us know
http://windows.microsoft.com/en-US/windows7/Open-Event-Viewer
What information appears in the event a log?
http://windows.microsoft.com/en-US/windows7/What-information-appears-in-event-logs-Event-Viewer