Slow Computer Problems

What actually causes a slow computer, and how to tell ordinary wear apart from a developing fault.

A computer that's gradually gotten slower over time is a different problem to one that's suddenly become sluggish or started freezing — the first is usually normal wear and a sign an upgrade would help, the second is more often a symptom of something actually going wrong, like a drive beginning to fail. Below is a detailed look at what typically causes a slow computer and what's worth checking before assuming new hardware is the answer.