Something is wrong but you do not know what. The machine is slow, an error returns, a device stops working: without the precise cause, you cannot fix the right problem.
What you can observe yourself
Note when the problem appeared and what happened just before: update, installation, drop or power cut. That information speeds up diagnosis a lot.
When to request a diagnostic
Intermittent issue hard to reproduce, unexplained error message, failure after an event, second-hand machine with unknown history.
Real case
Second-hand laptop in Pont-Saint-Esprit: heavy slowdowns and random shutdowns. Diagnostic: faulty RAM slot and hard drive near end of life. Two parts replaced for under €80, machine usable for three more years.
We tell you exactly what is happening before suggesting anything.
