Hello, welcome to CTH,
How long has this problem been going on?
I would maybe suggest that you try to restore your computer back to a date before you were having the problem.
To do this....
Click on Start >>> All Programs >>> Accessories >>> System Tools >>> System Restore
Here are some screen shots I made.....
Click on System Restore....
Click on next....
Choose a date that was before you starting having problems....
Click next and the system restore will start and you computer will restart after the restore is done.
Let me know if this helps