Changing out the power supply is easy, all of the holes will be in the right place. You need to change the switch also, depending on your case this may or may not be easy. Once completed, you will be restriced to hybrid mobos,they must be AT format with ATX PS connector. Many Socket 7 & Super 7 Mobos fit in this catagory. You will run into a lot of troubles if you try to put in a ATX mobo, that is when some major case mods will be necessary. I recently did this to my trusty old black tower into which I first installed a 286 in about '92. It is now a K6-2 450 in a FIC 503+.