Problem watching music videos in Itunes 7.6

[Orange Juice]

Hi there,

I was just wondering if anyone could help me out. I've got a load of music videos stored in the movies section of Itunes. When I open up any of the files, they start playing for a few seconds, but then there is a delay in picture and sound of about 10-20 seconds; the video then carries on playing, but not picking up from where it paused (hope that makes sense). All the files are mpgs.

The ultimate aim is to create a music video playlist which I can shuffle and edit over time, but it will be pants with this current situation.

One last footnote, my Itunes seems to be running a lot slower since I've added all these music videos.

I have a Macbook Pro (2.16 GHz Intel Core 2 Duo; 1GB Memory; Mac OSX version 10.4.11).

Any help would be really appreciated.

Thanks

OJ