Messenger knocking me offline

I recently got a new hp dv6000 series laptop with vista and brought it home
and integrated it into my existing network with 2 xp machines on it.
Everything seemed to work well enough after the initial Ip conflict was
worked out (which by the way I never had to deal with under xp, I believe
98SE was the last IP conflict I had to manually untangle). However now when
I start Windows Live Messenger (WLM) it signs in fine but after about 15-30
seconds it signs out and knocks me offline, sooner if I try to send a
message. I've been up and down help articles and tried several fixes.

At first I thought an uninstall/reinstall of WLM would help would help but
that didn't really get me anywhere. I've tried this with my firewall on and
off and WLM is fully allowed when it's on. I tried turning autotuning off,
but that didn't resolve this particular issue. The part of the problem I'm
not wrapping my head around is that all other internet applications work, IE
and Media center work, updates for everything that wants them works fine. So
my question is: Is this a network issue I just am going to have to
troubleshoot myself (ie buy a new router ). Or is this another issue
other people have had that I can get help with? Any help is appreciated.