Well well. Sorted it out. Very odd as it was the usb cable. Works on one machine but not on the other - Go figure!
As soon as I change the usb cable Ubuntu 12.04 was ok and in Windows 7 the nano driver installed no problem. I read reams of stuff on the net where people were having problems installing the driver in Win 7 for Nano, in many cases it could just be the cable. I was thrown off the scent as the Nano worked perfect in Ubuntu 10.04. Hope this helps someone.