I have these 2 movies, both over one hour long. when i aquired them, i would open them to play and it would only show the movie as just a few minutes long. if i were to move the advance slider it would show a later part of the movie that i wouldnt catch if i just let it play out. now for a few days it would play the movie in its entirety, but not anymore.

any idea what causes this to happen and how i can remedy it? btw, video card driver/software have been updated very recently