Remote Desktop Connection port 3389 not listening

Hi. We are having a problem with one Windows Server 2003 Enterprise Edition SP2 virtual machine. The Remote Desktop Connection to the machine was working fine until one day after a reboot. Then the port 3389 stopped listening for a connection. We could not connect again, yet we could make remote connections from the machine. We looked at some suggestions on Microsoft and some forums to change registry settings or the listening port, but it did not help. Then we installed Terminal Services Client 6 and the port would still not listen for a connection. How can I restore the Terminal Services settings to the default, so we can cancel any changes we made and hopefully get it back to working condition, or do anyone have a better suggestion?