make sure you buy something with at least 300w and up. There should be only 4 screws holding it on to the case. it slides right out. Your hard drive, floppy, cd or dvd and mother board will be connected to the power supply so be sure to remember where things are connected. Good luck.
Is it difficult to replace a Dell 4300S Dimension's Power Supply? I am aware that the Dell's require a Dell specific part, but am wondering if technically it is hard to replace yourself?