I'm tryying to edit a video but all I get on the media screen is the sound no visual only a blinking green screen, I'm using magix pro 15, I don't remember this ever happining before. Please help me.
IIRC this caused by an incorrect or missing codec for the video material you are using. What format is the source material?
Use GSpot to analyse the video clips and post the results here.
GSpot will also tell you if the codecs required are available on your computer - to test this click the buttons 1 , 2 and 3 in order - let each complete before clicking the next. To the right of these buttons you will get messages telling whether it is successful or fails.