When I am using my PC as my monitor, as well as using the speakers on it, with certain video files, the audio messes up. I can't understand why it is doing it, the sound works fine with most other audio/video files, and the files it doesn't work with work fine when I play them through my PC speakers.

Anyone got any ideas why this might be happening?

It is connected to the TV speakers through a cable which splits in to left (white) and right (red) audio cables for the TV.

The sound is squeeky and sort of sounds like it is speeded up loads.