@bo_lek
at first...thank you
the followed your instruction from point 1-5, although i clicked the R button, and now the player is visible in windows again
...so far, so good
but the next step to reactivate the hidden partition failed, although i followed your instructions
no hidden partition is shown...
futher, i opend the rk27dm software and choose tl-t50.rkw file, pushed the r-button and he started to do something. the operation seemed succsessful (without knowing what i has done). but nevertheless, the hidden partition doesen't appear