System restore is the only thing that kept my old computer alive for the last year or so. It's quite a simple thing, windows basically does it for you. But if you do it and then it goes horribly drastically wrong you're not allowed to hate me. Please.

You basically get to choose a date and 'restore' your computer to how it was then. Back when it was healthy, hopefully. You'll lose any programs you've installed since then, or the updates to them, but it should protect your documents and files. And if you've backed them up anyway then that's doubly safe.

I have no idea of this nursery rhyme of which you speak.