Slow computer, or failing computer? How to tell the difference
The symptoms that point to software clutter, and the ones that mean hardware is on its way out.
A slow computer and a failing computer feel the same from the chair, but they need very different responses.
Software slowness usually builds up gradually. Too many programs launching at start-up, a drive that is almost full, an operating system several updates behind, or a browser carrying dozens of extensions. It is worst right after boot, improves once things settle, and affects everything evenly.
Hardware trouble behaves differently. A drive that is failing produces long freezes where the whole machine stops responding and then returns. Files occasionally refuse to open. The machine may restart on its own or fail to boot every few attempts. Overheating shows up as good performance for ten minutes followed by a sharp drop.
The distinction matters because the responses are opposite. Software slowness is fixed by cleaning up and updating. Suspected hardware failure means stop using the machine normally and get the data off it first — every additional hour of use on a failing drive reduces what can be recovered.
If you are unsure, the safe order is: back up first, diagnose second, repair third.