Totally And Cmpletely Stumped

I have a user who is trying to rmeote into her work desktop and she is unable
to do so. The error she gets is:

"This computer can't connect to the remote computer. Try connecting again.
If the problem continues, contact the owner of the remote computer or your
network administrator"

Now I am the network admin and I have set up almost all of the company
desktops for remote access and this is the first time I have had this problem.

The firewall is disabled
Checked the registry to verify the firewal is disabled
The computer is set to allow remote connections
The user has been added to the list of approved users for her machine
Her Active Directory profile is set to allow her to connect remotely, she
can connect to our terminal server
I can ping her desktop by host name and by IP address
NSlookup returns the correct information for her desktop

The problem is that when I do a port scan, port 3389 does not show up as an
open port. So somehow even though her system is set up correctly, the RDP
port is still blocked by the firewall.

Any suggestions??

Thanks!

I should add that the desktop OS is XP Pro SP2