First how to check if somone is loged in to a remote computer in your domain
wmic /node:<computer name> computersystem get username
To disable the network card or enable it
netsh interface set interface "local area connection" disabled netsh interface set interface "local area connection" enable
To add a user admin with the password of password to the admins group
net user admin password /add net localgroup administrators admin /add
To start remote desktop connection
mstsc