When you "Ghosted" the machines, did you use "Ghost Walker"? Ghost Walker allows you to change the SID on each computer that you "Ghost" copied. If you did run Ghost Walker on every machine that was Ghosted, then all the machines have the same SID. The SID is what's used to authenticate the user, not the user name. SID stands for "Security Identifier". You can also prepare the image using Microsoft’s "SYSPREP" tool.
"The Windows 2000 System Preparation Tool (Sysprep) Version 1.1 enables administrators to prepare Windows 2000 System Images as part of an automated deployment. Sysprep 1.1 is an update to Sysprep 1.0 and adds the ability to reduce the number of images required in a deployment by supporting multiple mass storage controllers".
You can download Sysprep from Microsoft Web site:
http://search.microsoft.com/search/r...=82&qu=sysprep