It’s odd that the device isn’t accepting the latest firmware. You should be able to manage the files just fine using MTP mode, especially the resident wav files in the Record folder.
I’d manually select MTP mode and plug in the device. Then open the Device Manager, locate the Fuze under Portable Device (it will be here even if Windows Explorer does not show it). Look for the yellow warning triangle of doom next to the listing. Double click, or right-click, on the fuze, and select uninstall.
Lastly, unplug, then plug in again- windows will reinstall the device, restoring MTP. Recordings will show in the default MTP mode, as well as the original sample music that was loaded in MTP, if you have any of that remaining.
There are two main situations where the firmware is not accepted, if it is not unzipped (it should be about 15MB), or if it is not placed in the root directory. This can happen if you inadvertently roll the pointer over a folder when releasing the mouse button. If in MTP mode, you must expose th root by double clicking on Internal Memory first.
As far as freeze-ups on restart are concerned, do you see the refresh database mask? Thehe may be something that halts the startup process after booting. To cure this, format the device first from windows (right click on the device in Windows Explorer), and select format (avoid the Quick option).
Always, after formatting with Windows, unplug and start the device, and use the onboard format command under settings; this will optimize the memory with the proper cluster size.
Test that the firmware has been accepted (it should say Firmware Upgrade In Progress when you disconnect), via Settings > System Settings > Info.