I have one Windows XP SP3 pc on the domain that I cannot rdp into. The xp pc is enabled for rdp sessions. Port 3389 is open in the firewall. There are no errors in the event logs. I have tried to rdp from from a number of different machines running different versions of rdp client (5.1 & 7). When I try to rdp from an xp machine it fails without an error message, the connect button simply becomes disabled for a second and then becomes enabled again.
How can I troubleshoot this issue to find out the root cause?
Epilogue: I never did find the root cause....the pc had other faults and was removed offsite.
Step 1: telnet to port 3389 on the box. If you cannot connect with telnet to the port, you have a network or firewall issue. If you can connect, you have an RDP protocol issue.
Step 2: given that you have a RDP protocol issue, boot a Ubuntu Live CD (or similar) and try to connect using rdesktop. It may give you a different error message.
If you have a network-related issue, the question is wether it is a problem with the machine or some intervening equipment. If possible, direct connection with a crossed cable should isolate intervening equipment. You can also try to nmap the machine from where you try to do RDP connection. The pattern of available/blocked ports may give you a clue as to what is wrong.
This page has useful remote desktop troubleshooting tips for xp.