Disable_Account.ps1

#needs the SAMAccountName
$user = "afairfax"; 
Disable-ADAccount -Identity "$user" -whatif # confirm this is what you want
Disable-ADAccount -Identity "$user" -verbose

#check it's disabled. Will return false if it is disabled. 
(Get-ADUser -Identity $user).enabled

#re-enable the account when you're ready
$user = "afairfax"; 
Enable-ADAccount -Identity "$user" -verbose

#If the machine is not connected to Active Directory, or the account is local, try this
Net user afairfax /active:no