Everyone knows that as a computer gets older, it starts slowing down, but fortunately, there are ways to speed it up a little again. makeuseof.com has compiled a huge pdf e-book that teaches you how to do it. It also explains how to protect yourself against malware.
A lot of these methods have been around since like ten years ago or something, but not a lot of users took advantage of these methods. There’s also the fact that a lot of places had one tip to speed up your computer here and there, but now there’s a whole book on all of these methods in one place.