Wd my passport usb 3.0 external hard disk is not appearing on my computer

Hi I have had the same problem. when it does see a drive it trys to make me format it, did that on first one and same error after, took it back to currys and they changed it, new one does same.

I think/suspect that this is a problem with compatability of USB 3 to USB 2 not working properly.  This has been tried going through HUB and also direct into desktop.  Desktop is Sony Vaio VPCL 13S1E its got intel duo core, touch screen and is running windows 7.  unless get a result on this am going to take it back AGAIN and change to a USB 2 one or another connection.  

m16pab or Pete to friends.