Hello My Friend, Welcome to Just Answer.com. My name is Sandy and I am a Microsoft- Certified Technician who will assist you today.
Since how long are you facing this?
Is this computer a laptop or desktop?
did you make some changes to the computer?
Please restore your computer to the date when it was working fine.. Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. System Restore starts.