netwotk card no connection after reboot XP

Hi,

another setup. 2 computer and an access point.
Everything is working fine, till you reboot one of the machines. After the
reboot you get "network connection unavailable". Then you have to go to the
wireless card tool and click on the SSID and just press apply without
changing anything and you get signal/and strengh shown.
It seems the cards are not connecting to the access point by themself. They
are cheap cards (Excel) can that be the problem or is that something to do
with Windows XP.

Thanks
Matt