Can't connect wirelessly to TG585 v7

[#1]

We have two Windows XP SP3 PCs in our home office. One connected to router by ethernet cable (it has no wireless adaptor). The other has wireless (D-link) capability, but won't connect to broadband.
First up, got the "Windows is unable to connect to the selected network" message (PlusnetWireless comes up in the available networks) so followed Microsoft instructions and set up a new shared connection with the correct WEP key.
Now when I try to connect it just says "Waiting for the network" and then eventually times out.
All the lights on the router are green and steady. I've checked the interface type is correct in the Thompson gateway.
I'm at my wits end!
Any suggestions very gratefully received.

[#2]

The router uses WPA encryption by default
Does the wireless card support this
If it doesn't you will need to change the router to use WEP encryption
Do you have a any software for the Dlink adapter

[#3]

It's not clear if the wireless card supports WPA. I've looked at it under Devices and the WEP Option is disabled.
Not sure if I have any direct software for the D-link, but I can access many options under device manager.

[#4]

Do you have a model number of your wireless adaptor?

[#5]

D-Link AirPlus XtremeG+ DWL-G520+ Wireless PCI Adapter
I've looked on the D-Link site and it seems to support WPA and works for both IEEE 802.11b and IEEE 802.11g.
Until recently it was happily working on another broadband network.