I got this familiar error message earlier when trying to change the computer name of a Windows XP machine:
“Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed. Disconnect all previous connections to the server or shared resource and try again”
To get around this, I used the following netdom command from my PC (replace capital words with your own):
netdom renamecomputer OLDCOMPUTERNAME /newname:NEWCOMPUTERNAME /userD:domain\administrator /passwordd:ADMINPASSWORD /usero: domain\administrator /passwordo: ADMINPASSWORD /reboot:10
This renamed the computer and rebooted the little sucker in 10 seconds.