You're asking for a lot of headache trying to repurpose an old receiver. That case at newegg is going to have properly spaced holes for motherboard standoffs and a cutout in the back for the I/O. It'll have a mount for a standard power supply and mounts for optical and hard drives. Case fans are presumably included, with appropriate cutouts in the sheet metal. The front panel (including the volume knob) will be all pre-wired for directly interfacing with a PC motherboard. And I wouldn't be surprised to find that it has a built-in IR module (I didn't check).
Not that a DIY project wouldn't have its own rewards, but for mose people I think they'd end up with a nicer end-product and have a lot less grief by picking up a commercial product like the one linked in the OP. Speaking of the OP, was he even serious? His post has the tongue sticking out guy at the end of it.