OK, let me try and work through all of these!
I've tried another computer (unfortunately also runs Vista but only alternative I have) and not recognised in Computer or Device Manager
Unfortunately I don't have another mini-USB cable at present so can't eliminate that, but it was the one I got with the Cybook and worked fine previously and still works fine with my SatNav (not conclusive, but helpful)
Presence of SD card or not doesn't make a difference, but SD card in card reader (in any USB port) is fine and have checked for errors etc
I have tried different USB ports, no difference, and previous Cybook always connected fine
Laptop is plugged in, and the other computer I tried on was a desktop (USB I tried was at front, can maybe try other
Have tried several times at various stages of charge with no difference (I've had the 'new' one for a few weeks ago)
Have had to reset several times because the Cybook recognises the computer even though the computer doesn't recognise the Cybook so it crashes when I can't/don't disconnect properly (which is probably making the problem worse)
Only thing I forgot to do is try in safe mode so will do that time I'm restarting my computer and keep you posted
It works fine otherwise, it's just a pain; even though I use SD card a lot I should be able to transfer stuff onto my Cybook if I want to!
Nothing back from Bookeen yet.
Any more ideas gratefully received!