I was resetting permissions on my C drive to give everyone full control and the system hung. I rebooted and received the error message that autochk could not start, then I got a blue screen with the Fatal Error c000021a message. I tried to run it in safe mode and could not, I get the same message. I tried to go back to the last known good configuration and it still gave me the same error message.
I'm guessing my only choice is to reload Windows 2000 Professional. Any other ideas?