System Restore, as I noted, will not delete any user data/files. It is not a "reinstall", it's just a fallback to an earlier time.
System Restore is a Windows utility
that allows a user to restore their computer data to a specific former state (known as a restore point
), undoing changes made since that time. The user's personal data saved since that time (such as new files, new e-mail messages, and changes to documents) remains intact, but system changes are undone. System Restore periodically creates automatic restore points, called "system checkpoints" that protect data from unexpected problems. The utility also allows the user to create manual restore points before making any significant changes to the system, such as installing new programs or making changes to the registry