Yep, you need to buy a hub. They're affordable, not too costly.
Depends on the company and no of connections you want and the net speed of the hub.

Hi, please refer to this (http://www.annoyances.org/exec/show/ics_xp) article.
Please tell me if it does not help you.

Hi, just try reinstalling Firefox.

Disable the proxy server.

Hi, please post your HijackThis here (http://www.daniweb.com/forums/forum64.html) with a description of your problems