Hello Starbuk,
Welcome to the HP Forums, I hope you enjoy your experience! To help you get the most out of the HP Forums
I understand you are getting stuttering and lag when you are watching videos on your HP Presario v5000 Notebook. Since you already updated the drivers and you are still getting the issue I would recommend that you back-up up your personal files and perform a factory recovery on your Notebook. I know this is a lot of work, but it will ensure you are optimized and running smoothly.
To ensure you back-up your personal files I am providing you with an HP Support document: Backing Up Your Files (Windows XP). This document will walk you through the steps you need to perform to back up your personal files.
Next, you can follow the steps in the HP Support document: Performing an HP System Recovery (Windows XP). This document will walk you through the factory recovery process and ensure you have a system that is functioning correctly.
I believe this will resolve the issue you are experiencing when you are watching videos and let you go back to enjoying your Notebook. Thank you for bringing this issue to the HP Forums. Have a great day!