Windows 7 comes with backup utility allowing users to restore their computers to the previous operating state.
System restore can be performed by following the steps below.
1. Open start menu.
2. Type in rstrui.exe
3. Press enter or click on rstrui.exe
4. System restore window will pop up click next
5. Click next to restore computer from the last restore point or select “Choose a different restore point”
6. Click Finish and yes to confirm.
System restore will run for couple minutes and restart. Once computer is finished restarting all of the system changes should be reverted back to the system restore point selected in step 5.