You could use pspasswd from sysinternals tools.
usage: pspasswd [\\computer[,computer[,...] | @file [-u username [-p password]]] Username [NewPassword]]
computer
Run the command on the computer or computers specified. If you omit the computer name the command runs on the local system and if you enter a computer name of \\*
then the command runs on all computers in the current domain.
@file
Execute the command on each of the computers listed in the file.
-u
Specifies optional user name for login to remote computer.
-p
Specifies optional password. If you omit this you will be prompted to enter a hidden password.
Username
Specifies name of account for password change.
NewPassword
New password. If ommitted a NULL password is applied.