I use Sony Vegas 7.0 for about 14 days now and from the day that I installed it I'm having the same problem. When I try to edit clip (like cutting it to two clips or moving through the clip) it becomes pixelated. I don't really know how to describe it, but the whole picture becomes covered with small squares of very bright colors (pink, blue, green), usually only on places of the clip where I try to cut it or something like that. It looks like that moving through the clip somehow spoils it And after I render the video and watch it with another program, it remains pixelated on the same places.
I really don't know why is it so, or maybe there are some settings I should change... I hope that someone can help me here.
Thank you and have a nice day!