wifi stopped working XPpro SP2

Hello, I have a broadband account with Orange connecting through ethernet on my main PC.
My second PC is connected through a ZD1211B USB dongle worked fine for a couple of months with no problems, yesterday I was unable to connect through wifi. I have uninstalled the dongle and uninstalled all the USB items in Device Manager and rebooted a number of times and re-installed everything to no avail.
The wireless connection appears but is shown as " Not Connected" in Network connections.
Bottom right of the screen shows wireless connection logo with a red cross superimposed. The fifi dongle continues intermittently flashing so I presume it is OK.
I have run repair to TCPIP.Sys ntsh command and Stack repair netsh winsock command and rebooted also a number of times.
When originally installed, the dongle came with no software and the PC recognised it and worked fine. I have since downloaded a later driver but this still doesnt work.
I know that there is not a problem with the router as my laptop sitll works on its internal wifi.

Any ideas would be most appreciated.

 

As a test of the dongle, you could disable your internal wifi adapter on the second laptop and install the dongle in it to see if it actually is working.

 

Thanks Major. I have tried both the dongle and a spare dongle of the same make in the laptop and they connect without a problem. So still head scratching!

 

Any updates you are aware of or newly installed software at the time the connection was lost?
Could try a system restore to right before the time of connection loss.