D-Link Wireless Router issues

 pete -
I'm pretty new to this whole "setting stuff up" thing.
I got a wireless D-Link router .. it's connected to my desktop computer (windows xp). I was able to connect to my laptop (windows vista) and to my Wii, but it recently stopped connecting wirelessly. I can only use my desktop to connect. Any ideas what to do? (I tried to reset the router but thats as far as I got)