Put the usb stick in computer again and if you haven't alrady done so use safely remove hardware from system tray to remove it and see what happens. If doesn't work I'd just do the acronis restore to bring you back to a mth ago, no more point in wasting more hours on this, making sure that you copy any songs you have done in the last mth in the c drive to a different partition or drive on computer, and once acronis is done just copying them back to the right location.

joe