DVD through VIA/S3G CLE266 graphics card is jumpy

My friend recently gave me the PC that was being used as a router in our house. It’s a laptop motherboard with VIA/S3G CLE266 graphics card. As well as acting as a router we used to use the tv output to watch DVDs an VCD and such like.
I have now moved and am using it with a monitor and having real problems getting it to play DVDs. The only way I can get a picture is to turn down the hardware acceleration and then I end up with something so jumpy it’s unwatchable. Turning down the resolution or swiching from 32 to 16 bit colour does nothing to help. Anyone got any idea whether this is something I can fix or why this is happening with a monitor when two months ago it was fine to play DVDs on a TV.