Restore A Previous Version Of A File
If you improperly edit, accidentally delete, or corrupt a file through a system crash, in many cases you can restore a previous version of the file.
Every time you start your computer, Windows 7 takes a snapshot of its current contents and as you use your computer throughout the day keeps track of the changes you make to each file. This means you can reverse any changes you may have made to the file by reverting to an earlier version of that file. This action is called “previous version” in Windows 7.
TIP: Open the folder that contains the file you want to restore. Right click on the file. From the drop down menu click Restore Previous Versions. The files property dialog box opens. Select the Previous Versions tab. Wait a few seconds while the computer searches for previous versions. When the list appears, select the version you want to use and then click the restore button. Windows 7 asks you to conform that you want to restore the previous version. Click Restore and the previous file you selected is restored. Click OK and OK.
NOTE: If you are not sure which previous version to restore, click the previous version and then click Open to view the contents. If you want to maintain the modified version and the previous version, click on the previous version and then click Copy. Select a folder to store the file and click Copy.
Also note that this action may be used to restore a complete folder.