RDP Does not respond from workstation.

I have one workstation XP SP3 that does not respond to RDP request from any
machine. The RDP client just blinks when trying to attach.

I have taken the following step to trouble shoot.
Using Port Query the port responds. 3389
netstat -a shows the port being listened to. 3389
telnet does not respond.
when trying to restart terminal services I am not allowed however I have
rebooted.