I found something else you can check on through computer management as administrator; Go to control panel, administrative tools, computer management, click on storage, double click on media, or the expand + sign for media, locate and double click on libraries, or the expand + sign for libraries, locate and right click on your removable device for your sd card, select properties and view the general settings tab, look down at the bottom left corner of the general properties tab, ensure that "enable drive" is ticked/checked. Locate and click on the security properties tab on the top bar of the properties window for your removable device. In the Security properties tab you will find a list of users and options for what permissions each of the listed users have for this device. As administrator you can change the permissions for each user in this area, I suggest checking each of the "allow" options; "use" "control" and "modify" for administrators, power users and users. There is another option in the removable storage media tree, click on media and right click on your removable device, select properties and ensure the "enable media" is ticked/checked.