>>>Do you know of any freeware that would let block/unblock access to usb drives?
>>
>>You only need to change a registry setting, http://www.redmondpie.com/disable-usb-storage-in-windows-8-7-how-to-guide/
>>
>>In Tools->Task Pane->Solution Samples you find out how to work with the registry.
>
>Thanks Tore. I found similar info while googling. The thing is that I'd prefer a software freeware way to do it.

What can be more "free" than just a few lines of VFP code? Well, it's your decision.