network working but not sharing internet

[lone]

i have three xp machines. one is conected to dsl through a usb cable.when i plug in the eathernet cable for the network it shares files fine but the internet goes down on the computer. also when i try to set up the internet sharing with the wizard it tells me that the ip adress it need is already in use. can someone please help.

[lone]

i forgot to mention that i am using a d-link router. i can conect the dsl to the router and it works fine but someone told me that this is unsafe and i should run the internet through my main computer.