Are all computer parts compatible?

-I have two computers on with a good power supply and a dead hard drive and the other has a dead power supply and a good hard drive they are different brands I want to put the good power supply in the computer with re good hard drive is that possible? My freind is gonna build his own computer and I'm asking this for him "if I buy a Dell motherboard will it be compatible with hp drives and a IBM power supply" that is close to what he said idk if those are the correct brands but you know what I meanNot all computer parts are compatible. You have a better chance of getting compatible parts if the parts are with the same manufacturer ie. Dell, HP. But you cannot put Dell parts in an HP or vice versa.