What capacity and "type" of MicroSD card is it? I have gotten mine to mount a 32GB SDHC, but anything larger or of the SDXC type won't work.

One solution may be to carefully open the back using a flat screwdriver or other similar objects. Be careful not to damage the "snapping" connectors, I believe the back must make good contact with the copper "buttons" inside the device to power on. Next, disconnect the battery from the motherboard by pulling the connector "up" from the motherboard NOT towards the battery. I use an "eyeglass/ jewelry" screwdriver to do this. Wait a few minutes (I'm typing this post as I wait) then reconnect the battery to the motherboard. To check if this has worked, snap the back of the device back on and try to turn your device on (I know my battery still had a charge) and/or plug the device in to charge.