If you're using the word 'fuse' in the ordinary electrical sense, I've never seen one in a computer or any peripheral. I took a couple of hardware courses a few years ago and the term never came up. The only equivalent I know of is the circuit breaker that should be in the power supply and in the recommended power strip. I've been inside 2 or 3 dozen machines, many of them older ones, without ever seeing a fuse.