The most expensive repairs in any workshop are the confident wrong ones. These are the symptoms that lie — and the cheap test that unmasks each impostor before money moves.
Every guide in this set teaches that symptoms point at causes. This one teaches the necessary exception: some symptoms point at the wrong cause so convincingly that even experienced users buy the wrong part. A PC that looks stone dead may have one loose RAM stick. Random crashes that scream RAM may be a dying drive corrupting everything it loads. A graphics card condemned for screen lines may be innocent behind a damaged cable. The defence is not more knowledge — it is a habit: before replacing the part a symptom names, run the one cheap test that the impostor cannot survive. Here are the classic impostors and their unmasking tests.
👆 Example impostors. Each wore the costume of an expensive part — each was unmasked by a test costing minutes.
A machine that worked yesterday and shows no life at all today — no fans, no lights — wears the costume of a dead motherboard or power supply. Its commonest real causes are embarrassingly small: the power cable knocked half out, the switch on the back of the PSU flipped while moving the desk, a surge strip tripped, or a RAM stick or power connector unseated by the car journey to the repair shop. The unmasking routine costs ten minutes: different wall socket, cable pressed fully home at both ends, strip reset, then inside — reseat RAM and the main power connectors. Only a machine still dead after all of that earns a PSU test. Workshops see the loose version weekly; the truly dead board is the rare one.
Blue screens with changing codes are the RAM signature taught in the crash guide — and a failing hard disk can forge that signature. The drive corrupts the data and program files it serves, so different programs fail in different ways on different days, imitating memory chaos. The unmasking order matters: check the drive's SMART health before the overnight memory test, because SMART takes one minute. A drive reporting caution or failure explains everything and reorders the whole job — replace the drive, and the memory errors were never memory. The reverse impostor also exists: genuinely bad RAM corrupting files until the drive looks guilty. SMART status plus a MemTest86 run separates the twins; guessing separates you from money.
A machine that turns slow and strange the day after a Windows update is usually not infected and not dying — the update is still finishing: indexing, optimising and re-caching for hours after the visible install ends, sometimes across two or three restarts. The unmasking test is patience plus one look: let it complete a full cycle, restart twice, and check again before scanning for malware or pricing parts. The mirror image also misleads — real malware imitating hardware failure: pop-ups claiming the disk is failing, fake blue screens with a phone number to call. Those are not symptoms, they are advertisements from an infection; a genuine Windows blue screen never displays a support phone number. When the message wants you to call or pay, it is the costume, not the machine, talking.
When several unrelated things fail together, suspect what they share, not each of them. Keyboard and mouse dying together points at their common USB hub, cable or port — swap the port before replacing either device. Every USB device vanishing at once is the hub or the controller, not five broken devices. A laptop trackpad that clicks by itself and a keyboard typing alone often share one hidden cause — a swelling battery pressing up from beneath; that one is a safety item: stop using it and have the battery replaced. In offices, five PCs losing network together is the shared switch. The rule travels well: count how many things failed, then ask what single parent they share. Impostors survive on one-by-one thinking; shared-cause thinking unmasks them at once.
Watch impostor cases caught in the video — the dead PC that was loose, the RAM fault that was a drive, and the tests that exposed each one.
▶️ Watch Full VideoVery unlikely to be coincidence — moving loosens things. Check the wall socket, the PSU switch at the back, the power cable at both ends, then reseat the RAM and main power connectors. Most moved-and-died PCs revive inside that ten-minute routine.
Then believe the test and look at the drive: check SMART health, because a failing disk corrupts what RAM is then blamed for holding. Also test with one RAM stick at a time — MemTest86 is strong evidence, and together these two results corner the real culprit.
No. Genuine Windows blue screens show a stop code and a sad face — never a phone number or a support offer. A blue screen asking you to call is a fake, usually a web page or an infection imitating a crash. Close it, do not call, and scan the machine.