After reading your forum,,,,,,, by following the link, here is my advice:
By a new case, and new mainboard. Your HP seems to just be factory low-grade parts made for home PC, NOT gaming video cards.
1st, You can hardly EVER get any information on system - it's an HP, so the information is held secret.
So, if you have to by a case and new mainboard, you might as well buy a
1) ATX Case with 300 WATT P/S
2) Mainbaord for Athlon processor
3) Athlon processor -
4) New fan
Then you will have something that will run games, if that is what you want. If you only want to have SOME 3D video capabilities .... better than what you have now, you could just buy the NEW CASE & NEW MAINBOARD.