Please Help, Wireless Problem

Windows XP / Firefox 3.6.3</config>

I recently set up a successful wireless internet connection using a Gigaset SE572 WLAN dsl. However, after a computer update, it was switched back on and I was unable to connect to the internet. No wireless networks were found. I tried everything I could think of an probably did more harm than good, but I did manage to get it working again, although I was only able to do this by using the ethernet cable supplied.
I uninstalled , ran the set up cd again for a wireless connection and it says that no wireless antenna is found although mine is an internal one and was working just fine. The disc says that it canot complete the setup without this reciever. When I connect the ethernet cable and run the cd again for the wired connection it works. Ive checked that the automatic search is on in services but when I click the Network Connection page it says that no wireless networks have been found, this whilst the internet is working and the connections tab saying different, that I DO have a wireless connection. It also says that I have a local area connection that is shared{ which Im sure has changed from the inital setup} and another 1394 network adapter connection.
When I click on the status tab, I am now MISSING the wireless networks tab that should sit betwen the general and support tab. Its completely vanished and I remember this being there. The router is connected to this computer and a ps3 which the computer connects to with no problem. I have a high speed and the status tab says that packets are being sent but none recieved.
I am not that clever with computers and want to sort this out, if it worked perfectly without the ethernet cable I must be able to put it back as it was. Its all working fine, the internet connects, but it wont work wirelessly although the computer says its connected. Can anyone help?