Other Computer Will Not Recognize Network Security Key?

I have set up my desktop (has wireless) running Vista, which uses a broadband usb modem, AD HOC all was ok. Then set up the wireless laptop running xp, It reconizes the Desktop but wants a network security key(password). I tried useing the "password" that I used to set up the desktop with but the Laptop will not accept itSays the network xxxxxxx requires a network key(aso called a WEP key or Wpa key)....... Type in the key, and then click Connect.