Ridiculously slow download speed

I'm unsure where to post this. I have four computers at home, three wireless. Internet has been very slow. The BellSouth tech just left and after lots and lots of tests, plus a new modem, all computers but my main one are somewhat better.

Speed testing with Speakeasy shows that my main computer downloads at 1378 KBPS (Wired only brought it to 1394). Others are downloading at around 4051 KBPS. We uninstalled everything that we could think of that could cause a conflict. Nothing has made a difference.

This is a Lenovo T61p, much more memory, etc., than the other T61 I have. BellSouth said to call Lenovo. Lenovo said they won't help me because it isn't a hardware problem (premium support from them is less than worthless, I've found).

Does anyone have any idea how I can fix this? It's very upsetting.

Thanks so much.