Windows Issues with Windows Server 2003

Alright, I have windows serevr 2003 running on a dual xenon 450 system, 512 megs of ram 4 hdds. The issue I am having is that when I go to start up any program that has any connection from one computer to another which is not through somthing like windows explorer or opening files in winamp, the program closes. For example, I try to run Guild FTP on it and when I try to connect Guild FTP closes, I have also tried Bullet FTP, when I try to connect to that the ftp server shuts down (dosn't close, the ftp server shuts off). I also run Radmin, a Remote administrator program. When I try to connect to my server through it, the r_server.exe program dies. I have not done anything to change it, and I fear I have a virus, yet I have Norton Antivirus Corprate 9 running 24/7 along with ad-aware and neither are pickign anything up. I havent had any issues like these up until now, everything has run like a charm until recently. I've run out of ideas and I was hoping others would have some good ideas.
Thanks in advance

-Bob