Windows File Protection Warning

Earlier this week in my event viewer on my Windows 200 server I received many Windows File Protection warnings and I lost all the contents of my control panel and I can not access my adding users and groups anymore – on the users & groups it says “Unaable to access the computer “” The error was loading type library/dll. The event viewer warning is as follows “File replacement was attempted on the protected system file C:|winnt\system312520437.cpx. This file was restored to the original version to maintain system stability. The file version of the system file is 0.0.0.1. I have scanned for viruses and found none!!!! How can I resolve this problem?