I consider myself an average person when it comes to computers. The short answer to your question: we buy new ones.

A couple of weeks ago, my 5-year old very heavily-used laptop offered me three Blue Screens of Death in one week. I work from home and cannot take time to learn about computers. I just need mine to work.

The last BSoD happened the day before I left on vacation. there was nothing I could do but enjoy my vacation.

When I got back, I ordered a new computer and it arrived a couple of days later. The old one seems to work again for the moment, but I called a computer shop and explained what happened and they said it likely needs a new hard drive--$300. I will get it fixed so I can use it as a back up computer.

While I know next to nothing about computers and don't particularly care to know much more, I do defrag and back up on an external HD regularly. That is helpful. All my work stuff is stored on far away servers, so no work was lost.