Hi There
As you mentiond you do not use a router,
1: check your IP and make sure its a public IP
(start/run/ type cmd, then type ipconfig/all (hit enter)
Should be a public if no router/svr is used.
2: You mentioned connecting via localhost and it worked.
hit start, run, type cmd and in the dos window type "netstat -a"
this will bring up a list of all the connections and listening deamons with port numbers.
Make sure your ftp server is in the list and is listening on the public IP
3: If your running multiple network cards, make sure you have disabled the firewall on the correct card.
Also make sure you have diabled the firewall on the network card and not the loopback by mistake,
If your PC has a public address,(never post your real IP on public forums.) then I cant see why you cant connect using the IP,
if on the otherhand you were using NAT (network address translation) then thats the problem,
good luck and let us know how you get on
HTH
loz