In order to roll back to earlier date, you need to run the selected recovery point in the past. On Windows 7 / Vista go to "control Panel" in the start menu, select view – large icons or small icons, and locate the shortcut called "Recovery".
In Windows XP utility is a system restore is in the start menu" directory "Programs" - "Accessories" - "system tools" - "system Restore".
In the window system recovery, click open system restore". In the appeared wizard, restore system files and folders click "Next" and select a restore point that is more distant in the past from today's date, then click "Next" and "finish".
The computer will reboot, but if not, it will need to reboot yourself. Also before the reboot or after it on the screen you will see a strip of the recovery process. Windows starts in normal mode when the restoration process comes to the final, in other words, when the strip is fully loaded.