The call
By fifteen I was already running a small, informal repair business — word of mouth, house calls, cash on delivery. A computer wouldn't start properly, the owner said. I'd heard some version of that sentence a hundred times.
I arrived with confidence and a bag of software. No screwdriver — I didn't think I'd need one. Windows was misbehaving, throwing errors, freezing at odd moments. To me, at the time, that pattern meant one thing.
Malware. A dirty install. The obvious call, and the one I'd made correctly dozens of times before.
The first attempt
I wiped the drive and reinstalled Windows clean. Fifteen minutes of work, the machine booted fresh, everything looked normal. I collected payment, said my goodbyes, and left the way I always left — sure of the diagnosis, sure the job was closed.
Fifteen minutes later, my phone rang. Same computer. Same problem.
My first thought wasn't my diagnosis was wrong. It was: the client must have clicked on something already. It happens. People reinstall Windows and immediately reopen the exact file that broke it the first time.
Malware / corrupt install
Symptoms matched a pattern I'd seen and solved many times. The fix is fast, cheap, and almost always correct.
Failure after success
I went back and reinstalled Windows a second time — this time warning the client plainly: if this happens again, it isn't software. I'll have to take the whole machine with me. I didn't even own a screwdriver that day; every tool I had lived on a USB stick.
The investigation
Third call, same fault. I took the computer home. On my own bench it crashed too — but with a different error, close to the client's but not identical. Close enough to still smell like hardware, not habit.
I suspected the drive. Windows had failed to boot cleanly on it more than once, and a failing disk can throw exactly this kind of inconsistent, shifting error. I replaced it, reinstalled, and ran the machine hard for two or three days. Clean. No faults.
I delivered it back after lunch. It worked while I was standing there. Three hours later, that evening, the phone rang again.
The long road
By now I suspected the motherboard — which meant, practically, replacing the motherboard, the power supply, and the graphics card together. The client didn't need a discrete GPU; integrated graphics on a new board would do. Old case, new guts.
None of it was sold locally. The nearest city with real parts was 200 kilometers away.
I rebuilt the machine that night, reinstalled Windows once more, and used it as my own — it was the only computer in my brother's apartment, where I was living at the time. I ran it hard for over a week before I trusted it enough to bring it back.
I delivered the rebuilt machine. It worked while I watched. I left. Ten minutes later, my phone rang. I genuinely did not believe what I was hearing.
The power button.
Every internal component in that case was new — half of it, ironically, was hardware I'd pulled from the machine to build myself one of my own. The one part nobody had thought to suspect was the physical switch on the front of the case. It was sending a fault the whole time, and every diagnosis I'd made had quietly assumed the switch could be trusted.
What it taught me
Every diagnosis rests on assumptions you don't examine. Mine assumed the switch was just wire, and wire doesn't lie.
A repeated symptom is not proof of a repeated cause. Four different fixes produced the exact same crash, for four different reasons — except one wasn't a reason, it was the same fault wearing different clothes.
Sometimes the fix isn't the correct part — it's removing the point of failure from the circuit entirely. The client never touched that button again.
I ended up working on that one computer, on and off, for about a month — far longer than any job before it. It's the reason I still don't fully trust a first diagnosis, and it's a lesson that's followed me into every kind of debugging since, including hardware work I do today: a floating input pin on a repeater controller reads, on paper, exactly like a software bug — until you put a meter on it.
— Dmitrii, WH6HIS