We have 30 computers with the hardware all the same. we can boot all the comupters with a same Windows XP Image(by using DisklessAngel) over pxe. but the computer name will conflicts.

I wondered Is there a way to rename the computer at windows xp startup and take effect without rebooting?

You can use WSname.exe to rename the machine but it will require a reboot.

If you network will function with NETBIOS over TCP you can turn it off which would kill Windows ability to check for a dupe name but im not sure what side effects that type of setup would have

To try it:

Network Connections->Ethernet Adapter Properties->TCP/IP Properties->Advaned->WINS tab->Set NETBIOS over TCP/IP to Disabled

I have no idea what the side effects of such a setup would be but i do believe it should prevent windows ability to sense the other same named machines on the network.

thanks a lot, geek. I'll try your suggestion of disable NetBIOS over TCP/IP.