Why can't they just put another non-AC card in it? I think I read something about white-listing? and that I couldn't swap out the card on my own. That's just plain evil.
I would be willing to buy another router if you think that could be the issue, even though it still works perfectly with the other laptop.
Thanks for your help. I wish I knew more so I could help myself better, but I'm still reading and trying to learn this stuff.