CCleaner

I've downloaded a program recently that I've found quite useful, and which I think would be quite useful to lazy people who can't be bothered to clear their cache regularly (*hint hint*). Basically it does that, and resolves some differences between windows and the assorted programs you've installed forcefully on your computer, so it starts up faster. It's worked for me, my laptop starts up in like less than half the time it used to take (really!) and so I've included a link which you can find on the right side of my blog. Sorry it's only for windows though ;p