Black screen rendering? (can be random parts )

[Mintoni]

So i've been editing, and my project that was posted here was the only one which had a problem, i already unchecked the close media files when not the active application, and made sure that it wasn't muted or the split screen was depressed, though it worked in 360p, it didn't work in 480p, 720p, or 1080p

So what is causing this? is this a codec problem? is there a problem in my hardware? ( i have a really bad cpu)