Cross Cable RJ45 what is it?

What is a croos cabel that i read about? I went to local computer store to buy one and the guy asked what kind do you want? RJ45 straight on one side and twisted on the other or both end twisted. I'm trying to back up some DC games that I own. My DC has a Broadband Adapter installed and will not connect to my PC that has a New linksys nic card. I have read other post and they talk about a cross cable. So what one do i buy? I have a HUB as well and would like to run it through it, can this be done? And how in the world do i give my DC its own IP address? I have the IP-Load 1.0.0 and it sits at idle and don't do anything but piss me off. Will cable fix my probles? Pleas help..........