dammsaint, you are a "very idiot man", sorry but you are. The question is as legitimate as they get. It isn't blindingly obvious (especially on windows) and i don't think there's any obvious option for this either. Please enlighten us if you have the knowledge. And even it if were something really easy, not everyone is a tech wizard
I think that firmware needs changing to allow for this. Otherwise there's nothing to stop the system from mounting memory in read-write mode, which windows automatically does. I guess you could use a windows app to (re-)mount in read-only, but that doesn't really offer that much security