Inspiron 1545 wireless network issue with ATT Uverse

I can't imagine that I am the only one that is having this issue but here goes...

I have a 1545 and while at my sisters house in SoCal, I tried to connect to her network (which is ATT Uverse High Speed wireless). I could see her network but was not able to connect to it...either automatically or manually. I was online (on another wired computer) with ATT Uverse techs and we came to the realization that the driver that came on my Dell was the source if the problem(the most recent release I might add...as I tried to update it and got the message that my current driver was the most recent release).

I was initlally told by the techs at Uverse that it was because of the network security that was chosen to protect the network only worked with WinXP and the Apple compter that my sister already had on her computer...but was not compatible with Windows 7 which is what is installed on my latest laptop (1545). BTW, I was always able to connect with my old Dell laptop (WinXP)...so it makes sense that this could be true....until I pointed out to the techs that my brother-in-laws Windows 7 HP netbook was able to connect to the network as well.

I was able to briefly connect to the network when we disabled the security function altogether...so that rules out the card beng the issue (as I am also able to connect EVERYWHERE else wirelessly-hotels, airports, etc.) also rules the card out as the issue as well...The security setting on the router is set up for WPA2-PSK 

One other thing...if I tried to access another network that was in range...it WOULD ask me for the network key for THAT network...something that it never did when I tried to access my sisters network...WEIRD!

My question is....am I banished from ever using the wireless network at my sisters house? What are my options? Does any of this make sense?

LOL...thanks for any suggestions offered or opinions put forth!