Martin88, If the player is detected as an ADFU device this means that the firmware is corrupted. When the player is switched on it does a system check and finding the firmware unreadable goes into recovery mode as an ADFU Device. The only way to bring it out of recovery mode is to load a full version firmware. The fact that your player appears in the device manager as USB 2.0 (HS) tells me that your player is using one of the new Action chips so you will need 9.0.XX series firmware.
There are some full version 9.0.48 here:
http://www.mympxplayer.org/some-9048...ds-vt2895.html
and some full version 9.0.50 and 9.0.43 here
http://www.mympxplayer.org/full-vers...500-df413.html
http://www.mympxplayer.org/full-vers...043-df436.html
http://www.mympxplayer.org/full-vers...lcd-df430.html
There is only a slim chance that they will fully recover your player but once loaded your player should be detected by windows.