Has anyone else had this problem?

Unable to see local FL LAN server running on the same PC I'm playing on...
Two weeks ago FL was working fine, FLMM v1.2 installed with Tygrys Mod.
Went to a LAN bash on the weekend, changed Workgroup name to suit the
local network but have since changed it back. IP address also changed, once.
The only other thing that has changed is an upgrade from a TNT2 Riva 32
to a GeForce 2 MX400 32 (Finally, lol=) and reinstalled Detonator V.45.23
The machine is a P3 666, 133FSB, 384MB RAM, Video as above, 5.1DE Sound
(Yes I've read the other threads to try to fix the problem with the intro movie)
Op Sys is Win2K SP4, but again: It was working fine before the LAN bash...
Note: Another player has same issue, his mate can connect via LAN, he can't?

Thanks, awesome game... 6=)