Sequence editor problem. How to fix objects from becoming transparent?

I have a problem with the blender sequence editor. When I add two movies together, the objects in the animaton become transparent to some degree. This isint sopost to be happening, and I was curious as to how I can fix this problem?

Thank you!! and I hope there is someone that can help me.


What effect are you using. You might want to try the alpha over or under effects for a better result.