Wireless Networking Problem

["Chris" <c.nospamo@xxxxxxx>]

I have a home wireless set up using a Linksys Access Point (WAP54G-UK) which
has worked fine for a couple of years supporting 3 x laptops plus a
desktop - all running XP
One laptop has now stopped working - reports No Wireless Networks in Range.
Thought the internal wireless module may have failed (Actiontec Prism)
though Network Troubleshooter says everything is working normally.
Installed a new PCMCIA card (Zyxel G-120) - all appeared to install OK but
still reporting "No Wireless Networks in Range).  Borrowed a USB wireless
card (Inventel) and it works perfectly. Signal strength shows as near
maximum (the laptop is sited only a few feet from the Access Point) and it
can see several networks as well as my own.
Any suggestions as to how to identify what is wrong with my internal and
PCMCIA wireless ?

Chris