can’t join an NT-based domain from W2K

I have a PDC and BDC running NT4. Tried to change the name of a pc running W2K Pro, wouldn’t let me so removed from domain(!), changed local computer name and workgroupname, and now can’t rejoin domain. I get error (as per KB Q162797): ‘can’t log onto the domain .. the systems conputer account in its primary domain is missing..’
in Server Manager; on the W2K pc its: ‘the credentials supplied conflict with an existing set of credentials’ when I offer an Administrator username and password. Doesn’t seem to be anything I can do to rejoin (although I can browse the network from W2K pc), other that wiping the pc and reinstalling. Any ideas please? this must have happened to others although the MS KBase has nothing on the subject.