Spoke with client and they don't want to replace the video card and I don't blame them. I hate these types of problems when you spend hours on something but still can not fix it.
If VLC won't play it, it seems unlikely it will convert it. I'd try converting with Handbrake; if it doesn't work on the problem machine, try on a different machine that does play the problem videos.
Had a Win 7 machine have sound and video playback issues. Solution was to set Max Memory at StartUp. That was on youtube and various others. Not a specific file.