AT&T Air has connection problems specifically with personal computers

We just got AT&T Air, and it works great... on everything but personal computers. Phones? Great speed, good connection. Consoles? I downloaded a 50 gb game in half an hour, and played online games with no connection problems or lag on my end. Streaming on any such devices is fantastic.

The problem, as stated, is with pc's. On our pc's, the wifi connection is spotty, and never gets above one or two mb down. This is the case even when my pc is plugged directly into the router.

I am at a loss as to what could be causing this. Any advice is welcome.