look on the jumpers on the back of the harddrive. your 80gb drive should say Master, and your 30gb should say slave. Then on the cable there's 3 connectors. 1 for the controller, and 2 for harddrives, put the middle one on the 30gb drive and the other on the 80gb drive. And that's it... if you want to be able to boot win98 aswell you'll have to edit your XP boot manager. Don't remember how to do that, but it's not very difficult...