videos do not display anymore

Hi,
Everything seems to be ok. I have Quicktime 7.7.8 installed. I can import videos, I can see videos on the timeline, everything ok with the fps… but when I double-click on any video it doesn’t open the video window anymore. Same pb with an empty project. Have you ever experienced that ?

Thanks

David

Ok well I restored my computer with Acronis and everything is ok now.