...
For more information on System Restore, see:
Excerpt from MSDN on System Restore:
As the computer is used over time, restore points are collected in the data archive without any management or intervention required by the user. If the user ever needs to restore the system to a previous state, the available restore points are made visible to the user through the System Restore user interface. The user can choose any of these restore points. The only way to access this archive of restore points is through the System Restore user interface and the System Restore API; this is to protect data integrity and prevent accidental changes made by the user, applications, or other agents.
...