This imac is so old that it doesn't have a pannel that you can get into, that I can see anyway. It has what looks like 2 reset buttons on the right side where all the ports are. It has one that is a triangle and one that has a circle with a v in it. Do pushing either of these reset the PMU? How long would I have to hold them? If they don't reset the PMU then how would I reset it on one of these oldies? If it is one of those, how long would I need to hold the button?