They should know who originaly purchased the machine and if it was paid for!
If it has been paid for in its entirety then they shouldn't even care who you are as they are not owed any money on it!
If they are giving you gaff about weather or not your the original owner i would start threating lawyers and what not as they have no grounds for denying you password to a machine you purchased (if this is the case)
Its not intellectual property after all!
thanks
Michael T.
"If you don't stand for something, chances are, you'll fall for anything!"