Internet fast on Live CD but SLOW on HD install

Hello:
I'm a complete newbie to Linux and Knoppix. Plenty of experience with all windoze flavours and networking procedures though. I just received a Knoppixx 3.6 Live CD, instantly fell in love with the distro and decided to try a harddrive install on a test PC (Dell Optiplex PII 350 128Mb). The PC is connected to a router through an ethernet PCI NIC and CAT5 cable. Kanoppix work just great except for just one issue:

My internet connection (SBC DSL) works great when running Kanoppix from the Live CD... however it is PAINFULLY SLOW when I run the version installed on my Hardrive.... on the same machine !!!! :?

P.S. I have not done any kind of tweaking to the installs (don't know how yet) and all hardware was detected automatically. On my home network my router acts as the DCHP server.

Please Help and thank you for looking at my post !

Maybe this will work:
http://kanotix.mipooh.net/viewtopic.php?t=3400
:D