No sound in rekordbox

The first time i installed rekordbox everything was fine until after a few days the sound wasn't working anymore on rekordbox when i wanted to play a track. So in installed it onto another computer and thesame thing happend after a week. I haven't found anything to fix this and since reinstalling isn't an option due to all the work i put into it to sort all my music out, i don't really know what to do.

Does anyone else have thesame problem? is there a fix? 

any help is welcome

grtz