If you will turn off/disable System Restore, it will remove the copy of the infected file. That is if the infected file has been monitored too by System Restore (snapshot).
System Restore can't remove or heal a virus or any malware. It is just back-up copies of all items it is monitoring.
Some viruses are hard to remove. I have no problems at the moment, but is it possible to remove certain viruses by using system restore?