Invalid usrname 2k – 2000 lost password

Our Company has given a PC to another company we deal with. It uses a Database of our products etc which we supply free of charge (Database that is).
The PC is installed with Windows 2000 pro. The company have called to say they had a powercut/problem and when the PC rebooted it was asking for a usrname and pass. This PC is a local PC not networked. The main problem is our Admin is off for a weeks holiday and he set the username and pass for the company in question. Is there anyway i can bypass the username and password screen. Otherwise they won’t be able to login to the PC until our Admin comes back. Thanks to all those who reply – Posted on 16th April 2003 —
We cannot access this PC at all.