Quite proud of myself today. I found out what was causing my laptop to run 25% load on its CPU and sucking the power out of several small powerstations for several hours every time I turned it on. Which, since my laptop is rather powerful, is a lot.
Turns out it was only a couple of intensive processes from the maintenance software I use, which shouldn't have been running. And not a RAM-eating virus, as I first thought. But since I'm not terribly techy, I'm happy I managed to track down the cause and rectify it.