Curiosity got the better of me. Looking at it while in situ, I can't see any maker's name. MS 97** then VER 10 is in tiny print on one side. It has a substantial heat sink but no fan.
It was a 'refurbished' from CompUSA, but in mint condition when it arrived. A good deal at the time, but my guess is that it has a clone graphics card that reports as an Nvidia. Being an HP, I suppose it's under license, but who knows? The card may have been added by C-USA.