Hi,
- Were there any changes made in the Computer prior to this issue?
Perform the following methods and check if it helps.
Method 1:
Check if the issue persists when the Computer is in clean boot state.
**Step 1:**Check for the issue in a clean boot state. To do so, follow these steps.
a. Click Start, type “msconfig.exe” (without quotes) in the Start Search box, and then press Enter to start the System Configuration Utility.
b. On the General tab, click Selective Startup, and then click to clear the Load startup items check box.
c. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all. Click OK, and then click Restart.
**Step 2:**If the issue does not occur then, follow this article to find out the cause if the issue.
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
**http://support.microsoft.com/kb/929135**
**Note:**Make sure you put the computer back to Normal Startup once you are done.
Method 2:
Create a new User Account and check if the issue is fixed.
Create a user account
http://windows.microsoft.com/en-US/windows7/Create-a-user-account
If the issue is fixed, then fix the corrupted User Account by referring to the following article.
Fix a corrupted user profile
http://windows.microsoft.com/en-US/windows7/fix-a-corrupted-user-profile
Hope this information is useful.