Removing Domain info from XP Pro machine

Hello
Would use some help please.
Read some previous answers to similar topics but cannot find the solution to my problem.

A friend of mine got old DEL laptop laptop from the company he used to with…

He usually logged in using his old username and password as he used when he was connected to the company’s network, but couldn’t change anything in the machine, so he asked for my help.

I checked the network settings on My computer, and removed the Domain info writing a general name for a Workgoup.
Didn’t change anything on the Users age. After restarting as requested, I get the same login screen but old username and password won’t work… basically have no way to log on to windows now.

Any help greatly appreciated.
best regards
L.