Try not only net user /?
but also either
net help net user
net user /help
for the full syntax.
eg:
NET USER [username [password | *] [options]] [/DOMAIN]
username {password | *} /ADD [options] [/DOMAIN]
username [/DELETE] [/DOMAIN]
....
Options Description
------------------------------------------------------------------
/ACTIVE:{YES | NO} Activates or deactivates the account.
If the account is not active, the user
cannot access the server. The default
is YES.
....
