Networks

Hello
I have to change Local Administrators password on about 700 servers (Windows 2003/200. These are local admin accounts and have nothing to do with Domain. In fact I dont have a domain user account. Is there any way I can change the password through a script or batch file. I can use the following command to change the password but I have to logon to each and every server to do that manually
net user username newpassword
I tried using pspasswd command remotely but it gave me RPC error. Is there any command or script I can run remotely via RDP or VisionApp or Remote Desktop Manager (Devolutions) to change the local admin password. I mean the script can run automatically upon login via rdp and change the password via net user or any other command.
Any help would be greatly appreciated