I agree with Nuke. It should be Modem->Router->(Hub)->Lan
Hubs can create bottlenecks in high-traffic networks and I wouldn't use one unless I had to. If you have the same problem either your DHCP server is not working right(in this case your router) so you can try resetting ir or maybe there is a problem with the host connecting wirelessesly so I would repair winsock on it. http://www.majorgeeks.com/download4372.html Check that bad boy out.

-Oof