Windows Disk Protection is designed to help protect system settings and data on the partition on which Windows XP or Windows Vista is installed from being permanently changed.
The activities performed by a user during a session cause many changes to the operating system partition. Program files are created, modified, and deleted. The operating system also updates system information as part of its normal functionality. On a shared computer, however, the goal is to create an environment of uniformity for all users. Each user who logs on should experience the same environment as all other users, and no user should be able to modify or corrupt the system. Windows Disk Protection clears all changes to the operating system partition at whatever specified interval you set.
If you choose to turn on Windows Disk Protection, you can select the disk protection level that determines when and if Windows Disk Protection clears changes to the protected system drive.