Was wondering what happened to John.
Let me revise everything briefly so far (note that I'm at work and don't have any of the computers in question before me, so I'm doing this from memory!):
1. I have a D-link DIR-655 router attached to my PC - a Dell running Windows XP.
2. I have been using my laptop - a Dell Latitude running Windows XP - quite successfully on the router for some time now. Note however, that - I gather this is a quirk with Dell laptops - the wireless connection is not managed by Windows but by some kind of Intel PRO connection that I gather that Dell laptops use to connect.
3. I got an IPad 2 recently and tried to connect to the router but could not. The Ipad recognized the router but no matter how I put in my password XXXXX I used to configure the router, the Ipad keept saying it could not connect to the network.
4. With John's help, I reset the router and ran it without a password XXXXX security (I've been using WPA2 Personal AES or something like that). When I do that, both the laptop and Ipad connect to the wireless network and run simultaneously without a problem.
5. When I then password XXXXX router, however, only the laptop connects. The IPad recognizes the router, but I cannot connect when I put in the router password.
Note that to connect the laptop, I have to create a profile and change the generic name "dlink" to my unique profile name, and put in a WPS PIN number that came with the router. I don't know if this is what's causing the problem for the IPad.
That's it in a nutshell. I don't know what i'm configuring wrong.
Hope that you can help. Note that I won't be able to do anything on the system until this evening/tonight when I reach home.