Windows 7 System Restore:

Windows 7 System Restore is a backup tool that will help return your PC’s system files and programs to an earlier date. By restoring to an earlier point—a point before your computer began displaying problems—you may be able to easily resolve the problems.  

Steps:

1. Open the Control Panel and select System and Security.
   
   
   
2. Select the Action Center option.
   
   
   
3. Select Recovery option.
   
   
   
4. Click Open System Restore.
   
   
   
5. Click Next to begin the System Restore process.
   
   
   
6. Select a date and time you wish to restore to.
   
   

   Note: If you wish to find additional dates than those displayed, check the “Show more restore points” box.

7. Confirm your restore point by clicking Finish.
   
   

   Note: Your computer will restart and be restored to the date which you selected.