Connection problems when broadcasting wireless

in my apartment, we're broadcasting our wireless connection through one of my
roommate's computers instead of using a wireless router. while i've connected
and been able to surf before, i can't seem to do it anymore, even though my
"Wireless Network Connection (peer-to-peer)" in the bottom corner of the
screen says that I have an excellent connection. Does it matter that we have
three people trying to pick up his broadcasted wireless connection? The other
guys can pick it up just fine, but I'm having problems.

Any ideas or help is greatly appreciated.