Yksi ratkaisu
I used MSCONFIG to diagnose the problem (Start - RUN -Msconfig)
On the services tab I ticked "hide microsoft services"
This left services that were 3rd party services
I removed the ticks, saved changes and rebooted, the USB stick was now accessable
I ticked each one in turn and rebooted to find the service that was causing the problem
I found a service called "Admin Works Agent X6" which was causing the problem with the Memory stick