Unless they've changed, Compaq is pretty stiff about proprietary technology and parts (at least the 11 years I worked on 'em). You'd need to check with HP to see if they have a higher-wattage Power supply (HP bought Compaq a few years ago). 

Failing that, you might check some after-market suppliers in your area to see if they have something compatible.

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)