Playing an iTunes movie.

[MissLydia]

Every movie I buy or rent from iTunes plays fine on my iPod (4th Gen.) but not when I want to play it on my laptop through iTunes, partway through the films, it flashes different colours and breaks up until I pause it, leave it a while and replay it until it does the same.
Does anybody know why?
Thanks.

[Bigeye74]

go onto task manager when the film is running and see what is using up your memory. No doubt your laptop will have lots of thtings running in the background.