Problem with wireless adapter?

Hi

I use an Ei System 3089 notebook with Windows XP. A week ago I wasn't able to obtain wireless signal. I rang my ISP which is BT. The other notebook I have worked fine, so it was thought the fault lay with this notebook instead of with the router or BT. After going through a few checks it looked like this was the case. Normally when I booted the notebook it immediately found the wireless connection. The tech guy showed me that I needed to double click on the wireless icon in tray at the bottom of the screen, after using a cable to connect to the router to get broadband.

I would then get a window where I could refresh the network list. It would not be able to find the network. Then I clicked on "change advanced settings" and a new window would open.

http://i36.tinypic.com/2rmpb1e.jpg

I would click on the "wireless networks" tab. Then tick the box where it says "Use Windows to configure my wireless network settings". I would delete the network listed and then click on "View wireless networks".

http://i35.tinypic.com/fx6wcz.jpg

It would then usually find the network. Another small window would pop up asking me for the security key. Once I entered that, the problem was solved and I could use the internet.

Today, it won't work at all. It can't find the network no matter what I do. It uses a Ralink Corp 802.11g Mini Card Wireless Adapter. Can anyone help please?