Connection errors in windows

I've recently upgraded to Snow Leopard and decided to use boot camp to reinstall XP on a secondary partition. The problem I'm having is with getting some programs notably Trillian and Steam to keep their connection. Sometimes they work and sometimes they don't. I am in university halls of residence so I have had to set up some port forwarding to get Steam to connect at all but it's always tantalisingly out of reach.
Steam for example sometimes loads fine but then won't load a game it brings up the 'Game is unavailable' error. Sometimes I can get into team fortress 2 but can't locate any servers, sometimes I can get a server list to populate but cant load the game. Sometimes it doesn't even load Steam at all and fails on the updating step. Trillian has similar problems, sometimes dropping the connection and sometimes running perfectly fine.
At first I though this was a firewall issue due to the ports but after I managed to get each step to work at different times, just never together, I began to doubt that.
If anyone has any ideas that might help me sort this problem I'd be really grateful, there is only so much messing about with windows I can do without going crazy.
Thanks