To answer the question prior to your edit, do the following:
Open device Manager > Expand disk drives > Right click and then left click properties on the disk drive you don?t want access to while using Windows > At the bottom of the new window under ?Device Usage?, click the drop down and select 'disable the drive'.
Upon reboot you won?t be able to access the drive unless you re-enable it.
EDIT: This procedure just un-mount?s the drive from the specific windows installation in which you disabled it from - it won?t affect your other installation of windows. You can re-mount the drive by just following the same procedure and selecting ?enable device? it will reappear.