Video freezes constantly at same minute

(I'm sorry if the category is not the right one)
Hello! I have this problem with two of my video files .mp4 that I rendered in Sony Vegas 13, and every time I watch them, they freeze at a specific point and no software of any kind (repair video files) would help it... because it would still block at that same minute that my videos usually stop at, causing therefor for my whole computer to crash with no possible way of unfreezing it (but to shut it down). I really want to save these two video files. Thank you! (I wanted to attach a dxdiag with specs if it maybe helped, but I don't see any 'attach file' button). Also, I can't copy the file and even though I didn't try I probably can't delete them either. Anything I would do with them would make my whole computer freeze.