Randomly loses power

[evilmeister13]

I have two laptops that I'm trying to get up and running, they're both slow, but that isn't the issue. One of them is a dell with a single core celeron @3.3GHz with 4gb ddr3 ram. When i power this one on, i always turn on the task manager just to check it out. (I always have the task manager open to keep an eye on my performance.) It instantly jumps up to 100% on the cpu, and slowly but steadily creeps up to 100% on the memory. That bothers me, and I'm assuming that's why it's really slow. However, what really bothers me is it will be running slowly, then get super super slow, then it loses power. It makes a little popping noise and the screen goes black, leaving me sitting there going ????wtf???? the other laptop is a toshiba with a dual core i3 @3GHz  with 6 gb of ddr3 ram. it doesn't jump up to 100% on the cpu and memory, but it will all of a sudden move super super slow and then lose power. Any idea what's going on? Both of them will lose power even if they are plugged up, so I'm assuming the battery isn't the issue here.