System Restore is a component of
Microsoft's Windows Me, Windows XP,
Windows Vista and Windows 7 operating
systems that allows for the rolling
back of system files, registry keys,
installed programs, etc., to a
previous state in the event of system
malfunction or failure.
In System Restore, the user may create
a new restore point manually, roll
back to an existing restore point, or
change the System Restore
configuration. Moreover, the restore
itself can be undone. Old restore
points are discarded in order to keep
the volume's usage within the
specified amount. For many users, this
can provide restore points covering
the past several weeks. Users
concerned with performance or space
usage may also opt to disable System
Restore entirely. Files stored on
volumes not monitored by System
Restore are never backed up or
restored.
System Restore backs up system files
of certain extensions (.exe, .dll,
etc.) and saves them for later
recovery and use. It also backs up the
registry and most drivers.
Source: Wikipedia
