HP cases only work with with HP mobos.
semp
Not quite true. At least all of the recent (= post win98 era) HP tower desktops have been standard at least on the motherboard side. Some of their PSU's were of different shape, though, especially in the professional workstation models, but even they have become mainline.
There's one thing to look at when refurnishing a HP case with a different motherboard, though: Many HP cases have bulges with screw holes instead of detachable feet. Some of them have the said bulges also below the processor, designed for secure mounting of a certain type of cooler. Of course they may cause shortcuts if their placing isn't suitable for the new motherboard, in which case pieces of electric tape will help. But basicly they are standard, often micro-ATX or the upside down version of the same size.
A totally different thing is the HP installation media and a non-HP motherboard (applicable for any other brand). They don't mix. A brand specific OEM license code on the case will usually work with a generic Windows installation media of the same type, though.
