Error Message

Anytime I try to open AIM or when i reboot my system I receive the error message "The procedure entry point rtlIsthreadwithinloadercallout could not be located in the dynamic link library ntdll.dll". I have tried restoring my computer but it won't open and when I go to "open as" it says "You do not have sufficient security priveledges to restore your system. Please contact your administrator, or logout and login again as the administrator". I am the only account on my computer so I'm under the administrator's account. I think there is something wrong with my sysem tools but I have no idea what to do~!

HELP!!

Thanks!

Bethany