first off, can i use a modem and crossover cable together? because when i plug my lan cord into the router it refuses to aknowledge it and my xbox and second comp wont accept it.

and when i plug my xover cable directly into the modem its recongized and my xbox recognizes it, i even downloaded a skin for avaluanch to be sure.

so why cant i get Kai to work? how come my xbox wont accept the connection if i go through the router?

im a bit confused as to your setup .. you don't need a crossover cable unless your plugging the xbox directly into the back of your computer .. the crossover cable may not work plugged into a router unless you have a 'smart' router that auto switchs .. just plug the modem the xbox and the PC all into the router with regular LAN cables .. make sure you can get your network working before kai .. heres a guide to xbox networking ..

http://www.chefelf.com/xbox/networking.php