How to prevent graphics from getting worst when editing with Movie Maker?

Tzeentch1

Honorable
Nov 16, 2013
4
0
10,510
When I drag the video into Movie Maker graphics are ok. When I press "Add Title", graphics become extremely bad. You cannot see anything! Do you know what can I do to prevent this from happening? Please give me a solution.
P.S.: Some months ago videos were being edited well. When I tried to create another video, this started happening.