Okay, for the record, the machine that I had the vids running fine on has the following spec...
AMD Sempron 2800+
1GB PC3200 RAM
Generic Winfast Mobo
ATI FireGL 9700
The vides were skipping on the same machine when it was using O/B graphics and only had 512MB RAM.
I think it is down to the graphics card, as the videos were skipping slightly on my 64x2 machine with 2GB RAM, when I ran it through the O/B graphics!
I am looing at getting an ATI 9200 with a decent hun of memory, hopefully that should solve the last semi-issue that I have with Malas performance (when chaning menus, the fade effect is very jumpy).