Help Me!

I have a single mac on a home network of 3 PCs. Recently our old internet hub broke and so we got a new one, the D-Link DSS-8+. Ever since we got this, my internet connection has been drastically slowed. We're talking 4/Kbps!!!!!!!!!!! I have no idea what the problem is. The PC's connections are fine, and they're on the same hub. HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!