You may have to force-feed XP the drivers. HP swears that this model uses 6150, and any use of a 6150 specific driver from HP will result in a fail error when installing. So...
ftp://ftp.hp.com/pub/softpaq/sp33501-34000/sp33549.exe - If this softpaq doesn't work, try grabbing another geforce driver from another HPaq laptop. It should work though.
Try extracting that EXE and then force-feed the driver (go to device manager, right click display adapter [might be called unknown device], click update driver, and then direct it to the directory where that softpaq is extracted to). Since HP doesn't officially recognize the 6100, their software checks your system for 6150. When it sees 6100, it fails thinking it's a completely different model (even though the driver is pretty much identical for both IGP's).
Also, you should install your chipset drivers before installing graphics!!!
Good luck.