OK, I realise my last post was a bit top heavy and that's probably why I didn't get a reply. So now I've cut out all the fat:
I have a PC with a dual boot, (Windows and Ubuntu Dapper Drake) and it connects to the internet via a Thompson usb wireless adapter. I have dhcp enabled. The Windows part of the connection works fine but the linux half has no network connection. I installed the ndiswrapper-utils module supplied with the CD, and then the Official driver (downloaded from the Speedtouch site) via the ndisgtk interface. Then I ran the ndiswrapper -l command which confirmed:

driver present hardware present

But no network connection. iwconfig confirms the access point is not present. However iwlist wlan0 scan lists 14 networks detected including my own. Then I discovered something interesting. I tried uninstalling and reinstalling the driver. Only this time I installed it using the sudo -i command instead of ndisgtk.Except that now I got the message

couldn't copy drivername at /usr/sbin/ndiswrapper line 135.

When I checked with ndiswrapper -l it said 'invalid driver'. I thought I'd copied the file name wrong but no matter how I copied it I still got the same error message. So I reinstalled it using the ndisgtk interface and it installed perfectly. Except that I still have no internet. Could there be a connection here?