I have an older computer that runs XP when i watch dvds its a bit jerky. If i go to milenium will this help?

I have purchased a new graphics card and i have 386 mbs of ram. The jerking used to be really bad as in it would take 10 mins to play half a minute of video. Now it up to speed but has a slight jerkyness to it. As in the sound kind of jumps and video. Please help.... or any other suggestions. Also the processor is 700 mhz or something like that. However i really don't want to upgrade the motherboard etc. Thanks