Try loading the Last Known Good Configuration.
Follow these steps:
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 Lock 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 will 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, and then press F8.
3. On the Advanced Boot Options screen, use the arrow keys to highlight Last Known Good Configuration, and then press ENTER.
4. If your computer has more than one operating system installed, use the arrow keys to highlight the operating system that you want to start by using Last Known Good Configuration, and then press ENTER. Windows will then resume starting normally.