black screen while playing every video file - problem

[cawboy12]

Hello,
I have a strange problem on my cowon o2 when I play every video file there is no video (black screen) and only audio is playing.
It started when I was watching movie and video have frozen. When I turn on the player once again the problem started.
This is not the codec issue because I played files that this player should easily play. Other features like playing music files and watching pictures files are working.

Have any of you had this kind of problem. I updated firmware to the newest available but the problem is the same.

I will be very gratefull for any help.