Have a PC upstairs and XBOX down. Can't run cable downstairs how can i hook up to live w/o wireless router?

You can't. Get the wireless router.

I'm assuming your cable modem is also upstairs? Your choices are wired or wireless. Without a wireless router you don't have a wireless connection that your XBOX can use so in that case, it must be wired. If you can't wire it then you're screwed. I have my PC's on wireless cards upstairs, and then my cable modem with wireless router and AP downstairs, next to the PS3 which is hardwired to the router (although it could be wireless as well). Why not just get a wireless router? They don't cost that much and it will add a lot of benefits to your current home network setup.

The best answer...is go purchase some equipment. Every other new-fangled advice I could give you (oh, you could just run a cable to your computer's 2nd Ethernet port and bridge connections!) is just going to compromise your gaming experience... 1) Go to Wal-Mart or a local, big chain electronics store (not Best Buy! Like, Micro Center!) and get yourself either a wireless router or a wired router. 2) I'd stick with the wireless 3) Go to GameStop, see if they have used Microsoft Xbox 360 wireless adapters. They probably do, for cheap. Or go buy one of the third-party adapters at same Wal-Mart or Micro Center. 4) Configure router and antenna. 5) Play wirelessly. I know it's not what you wanted to hear...but I wanted to tell you, because frankly there's not much better of a way to do it in your circumstance. Sucks.

Basically, there are 3 options - here they are from chepaest to most expensive: 1. run wire 2. wifi 3. Powerline Eithernet I'd suggest wifi unless you have some reason a wireless router won't work...otherwise your last choice is Powerline Eithernet which will be about $120US for a cheap kit.

have you got a laptop you can put your laptop downstairs and make a bridge connection so your latop shares the connection with xbox :)

c