Change from Win2kNTDomainServ-W2K Member

I have a DELL PowerEdge2500 – having Windows 2000 – NT domain Server installed and partitioned. I want to change to Win2k – Member .

Can any one suggest whats steps should I perform.

– I tried reboot thro disk and Selecting clean up – option from Windows 2000 Server CD. When It asks for 3 Options
1. ENTER for setup
2. R – for Repair
3. F3 – to quit

when I select 1 or 2 It gives an error Hard Disk Not found ????

Thanks In advance …