Do you see a brickwall in front of the small globe in the left bottom corner of the LW window??
If so, it means that you're firewalled.
Do you use the exact setup for LW and BS on the other 2 computers??
Okay, for LW I would reckon you try to delete your " .limewire " preference folder as discribed in this thread (with LW completely closed, i.e. also in the system tray):
http://www.gnutellaforums.com/showth...threadid=36420
For Bearshare, hmm I've just started to use it by myself, what BS version do you use?
Did you try to "Force to become an ultrapeer"?
The function is located at Setup>Service at the bottom (at least it is there in my version).