Dell Studio, Win7 - Won't connect to new AT&T Uverse Wireless?

Hello all - and thank you in advance for any help you can give me.

We just had AT&T uverse installed in our apartment yesterday, including wireless internet.  We have two laptops in the house - the first runs Vista, and it found and connected to the new wireless signal no problem.  

The second computer (Dell Studio laptop) runs Win7, and it see's the signal, but when it tell it to connect, it says, "Windows was unable to connect to this network."  It doesn't even take me to the step where I'd fill in the network password.

I spent an hour with AT&T support last night, and they tried quite a few things before finally saying it is either a Dell or Windows problem.  I've done a bit of searching and it seems this is a somewhat common problem, but I haven't been able to find a thread which gives a firm solution.  Some suggested a driver issue.

I could use a little help here, before I'm forced to call Dell support and pay the fee for them helping me.  

Any thoughts?  Thank you!