Firstly, I would like to thank Steve and the members of this excellent forum for their timely and helpful responses to my original cry for help.
The replies I received indicated the problem was that the WH1081 wasn't being recognised as HID compliant. With that clue, I went searching on Google, and eventually found this thread: - http://forums.techarena.in/portable-devices/1125053.htm , post#2. All credit to Maxforu for the answer. In case the forum goes down, here is the post: -
"The problem is, as stated, a Human Interface Device (HID) in combination with update KB938371. After installing this http://www.microsoft.com/Downloads/d...displaylang=en update , my usb-mouse stopped working. Just go to device manager --> HID-devices --> Unknown Device and search for drivers. Vista will not find any drivers online, so you have to search for drivers on your own computer. The location of this driver (in most cases) will be C:/Windows/Winsxs. You will get a popup saying "this is an unsigned driver bla bla bla". Just install the driver. The mouse worked for me (even without reboot)."
Now, I Know this was Vista and a mouse, versus Windows 7 and a weather station, but I thought why not? The message changed to installing driver. After that, the device was installed, and I can collect data on Cumulus.
Happy days! Once again, thanks for making me welcome on here. I hope in time I can be of some help to others.
...I have gone through a similar situation on a small desktop computer running under Windows 7 Home Edition 64-bit - good thing I had a software reinstallation DVD... 
