Did the HP ship with a copy of Windows and a recovery DVD with a passcode? Then that might work, sure. I'm not saying it wont work, I'd look into it. =) Just out of curiosity what are your plans for the comp after the case swap? Because if you have a good chip and motherboard and you're into overclocking and gaming you'll want a good video card and that will need a good power supply. Also the aftermarket motherboards run faster RAM then what comes with an HP so at some point you might end up upgrading that. Sooner or later you might not have any parts left over from the HP! lol. Good luck with it...
xoxo
- Joyce