Are you able to boot into Safe Mode?
If yes I would suggest you to boot into safe mode and perform a System Restore.
Safe Mode:
Safe mode is useful for troubleshooting problems with programs and drivers that might not start correctly or that might prevent Windows from starting correctly.
1. Remove all floppy disks, CDs, and DVDs from your computer, and then restart your computer.
Click the Start button, click the arrow next to the Shut Down button, and then click Restart.
2. Do one of the following:
· If your computer has a single operating system installed, press and hold the F8 key as your computer restarts. You need to press F8 before the Windows logo appears. If the Windows logo appears, you'll need to try again by waiting until the Windows logon prompt appears, and then shutting down and restarting your computer.
· If your computer has more than one operating system, use the arrow keys to highlight the operating system you want to start in safe mode, and then press F8.
3. On the Advanced Boot Options screen, use the arrow keys to highlight the safe mode option you want, and then press Enter.
4. Log on to your computer with a user account that has administrator rights.
When your computer is in safe mode, you'll see the words Safe Mode in the corners of your monitor. To exit safe mode, restart your computer and let Windows start normally.
For further information, visit the below mentioned link:
http://windows.microsoft.com/en-MY/windows7/Start-your-computer-in-safe-mode
Sytem Restore:
http://windows.microsoft.com/en-US/windows7/System-Restore-frequently-asked-questions
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