To restore the registry, run the program and go to the Action top menu -> Restore Registry From Full Backup. The System Restore utility can also be launched from the All Programs -> Accessories ->System Tools menu.
System Restore starts. On the Welcome to System Restore page, click Next.
On the Choose a Restore Point page, select the most recent system checkpoint and then click Next. On the Confirm Restore Point page, click Finish. System Restore restores the previous Windows® configuration, and then restarts the computer.
Log on to the computer as Administrator. The System Restore Restoration Complete page appears.
For additional information about System Restore, click Help and Support on the Start menu. In the Search box, type "system restore", and then press ENTER.
If Windows® fails to start.
Restart Windows® by using the "Last Known Good Configuration" feature: start the computer and then press the F8 key when Windows® begins. The Windows Advanced Options menu will appear.
Use ARROW keys to select the "Last Known Good Configuration" and press ENTER. Windows® restores the computer to the most recent restore point.
If the above does not help you can run System Restore from the Safe Mode. Boot into safe mode, log on with an administrator account and type into the search prompt or command prompt: rstrui.exe. Then press enter.
Warning! Make sure that your backups are current. If you restore an old backup it could be fatal if you've made major changes to the operating system or hardware since the backups were created. For example, if you've installed Internet Explorer 9 and restore your registry from a backup predating that, expect that your computer won't work properly.