Model: HP Pavilion 6640C
Operating System: Windows 98SE (Note: might work with other versions of this os.)
Before downloading: Run Free Scan for Instant Driver Updates
Simply download, extract the file, then run the setup utility and reboot. The screen might not be filled out at first, but simply change the screen resolution, and it will work fine. I would assume this driver will work with all prior version of Windows before Win 2000.