There are motherboards that you can buy that will be compatible with your pavillion. The trouble is, you might have some difficulty finding one. If you can, and it's considerably cheaper, then buy it. On the other hand, if it's too complicated, buy a normal case along with the motherboard.
The most common problem with buying certain systems is usually just the motherboard, case, or insufficient amounts of resources (such as RAM or hard-drive space). I doubt that you will encounter more problems because of the case, though. Everything else, such as the power supply, hard drive, floppy drive, and CD/DVD drive should fit just as it would in any other case.
I hope this answers your question. If it doesn't, let me know.
I bought a desktop pavilion8655C /Win 98se OS. I should have learned then, but I was a real novice with home pc's. calling tech support was the worst mistake I made. each time I was worse off. now I need to add more memory, but I have a burned out connection on the motherboard(Asus Hawk1.0 when I spoke to different purveyors they all said that the board probably wont fit in an HP case because they put their screws in different places. This makes me wonder if I am going to encounter other such instances
or if I should just get the board with a case that it will fitand trust that everything else will fit in place. Any info regarding this and my best course of action would be appreciated Much thanks, Lafitte