Unable to connect via RDP or CONSOLE login. Cannot access PST file

Hello,
I am unable to connect to one of our fileservers via RDP or console login.
Trying to login via RDP just seems to refuse connection. I can ping server
and TELNET to server. It is setup for Remote desktop too.
Server is part of a server farm on ESX boxes. Loggin onto ESX I can open
console to server with no problems, but cannot access from any PC.

Also, this happened two weeks ago, possibley after a windows update as the
server has rebooted over the weekend. Problem does not seem to affect any
other server.

Other wierd thing is that none of our users can access thier PST files
either. All other files accessible via mapped drives.

Any suggestions would help as I do not want to reboot server during working
hours !

Thanks