Hi,
· Did you make any software or hardware changes on the machine prior to this issue?
· Do you have Lexmark printer installed on your computer?
Let’s follow these methods and check if it helps.
Method 1
If you have Device Monitor software installed, you may uninstall it from Program & Features. Thereafter, reinstall it and check if the issue persists.
Method 2
If ‘Method 1’ doesn’t help, you may configure the computer in clean boot and check if the issue reappears. It will start Windows Vista by using a minimal set of drivers and startup programs and helps to eliminate software conflicts.
The following link has steps showing how to perform clean boot: http://support.microsoft.com/kb/929135
Note: Please ensure that the computer is set to start as usual by following the step 7 from the article: How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows7: http://support.microsoft.com/kb/929135
Hope the information helps.
Please post back and let us know.