Most likely hidden.
If it was previously viewable from the Welcome Screen, and now it's not, you can press CTRL+ALT+DEL twice and you will bypass the Welcome Screen to go to the old Windows 2000/NT logon prompt.
After which, just go into the control panel doohickey/group policy, etc., and reconfig that bad boy.
The exact procedure currently eludes me, but the 2-3 finger salute should get you in...
Cheers,