2 Laptops, only 1 can be on WAP at a time

Hello all, I have been having a problem for a while now. Basically I have 2 WAPs set up at my house (on non overlapping channels). One is a DLink and the other is a Linksys. Both are set to be in Mixed mode b-g (though we have tried G only), and both are using WPA PSK. We have 3 Laptops, all of which are Dell 700Ms with the Intel A-B-G Card. They are all also running Windows XP with SP2.

Here is the problem though, only 1 Laptop can be connected to a given WAP at any one time. Once a second Laptop connects to the WAP, the first one becomes disconnected until the user forces it to connect back to the WAP, which then disconnects the other user. So basically it is Last one in wins, and the other person just get disconnected. This happens on both of the WAPs. I have tried using different software to control the conection (Windows software and the Intel software). We have tried different security types (WEP or WPA). I have tried other things as well. I have searched and searched, but still have no answer for this problem. Perhaps someone else has some ideas.

Ike