K so for some reason now it works...I clicked around for hours and I think this is what I did:
After installing the 64bit drivers and also the ones from the samsung page, put the device in storage mode and connected it.
When the message for USB device not recognized appeared I went to device manager and manually updated the driver...pointing it in turn at each folder in the 64bit driver install until I got to one that managed to not give an error 43...was able to get the card & phone storage to show as drives in my computer.
Switched to Media player mode and had same problem...turned off phone & restarted computer and now works. So confused.