If you do not have enough disk space available when your operating system is installed, then you must turn on System Restore, using the preceding steps, after you have made sufficient disk space available.
If you run out of disk space, System Restore becomes inactive. When you have made sufficient disk space available, System Restore is automatically activated, but all previous restore points are lost
When System Restore is turned off on a partition or drive, all restore points stored on that partition or drive are deleted. Changes that are made on an excluded partition or drive are not reverted during a System Restore