Ok, we have a router and modem and everything connected upstairs, and three computers in the house using wireless usb adapters to get a signal from it. 2/3 of the computers are fine, the other one is constantly loosing signal strength and booting offline. It just cant keep a steady signal, and its practically below the router.

. We just gave up on wireless and wanna go wired. Is it a contractor I need to call, too have a cat wire ran from the downstairs computer up to the router in the upstairs room (through the wall)? thats what contractors do right? ... another option.. Could I buy another cheap $20 modem on ebay, and just use that with the open cable line downstairs for the computer thats messing up? Would that work? Even tho, I already have a modem and router upstairs?