what a pain, but got there in the end. using vmware I couldn't get the vm to connect to internet, tried a few things, and to be fair, I got bored and thought I'd go back to virtualbox.
so uninstalled virtual box again, and deleted my settings, and all remaing files in program files. reinstalled VirtualBox-4.3.12-93733-Win, created a new vm using existing virtual hard disk, and all ok now
still had to reboot the pc after it started to get network to work