If you have a microSD card in there take it out, switch on, see what happens.
I have no idea why, but switching between MTP and MSC can sometimes lead to weird behavior that ends if you are just using internal memory. You may well be able to format the unit with the command from Settings/System Settings.
Stuck on Refresh can also mean a bad sector that you can fix with chkdsk when connected to the computer (or Properties/Tools/Error-Checking/ on the drive).
