Look in the registry and system ini files for vspf_hk.vxd and remove references to it especially if in the StaticVxds bit of the registry. Search your system for ntdll.dll - missing export messages often mean you have 2 of the same file, the one in SYSTEM or SYSTEM32 is the one you want to keep delete the others (usually in a program folder). You can also try RNIS.EXE if your NIS was 2003 or earlier.