Every winter we get the same call from the Midlothian villages, and it always follows a night of wind: the power went off and came back on, and now the desktop is completely dead. The customer who prompted this guide was in Lasswade, and the first thing she said was not “can you fix the PC” — it was “are my photos gone?” That is the right question, and the honest answer is almost always reassuring. A PC that is dead after a power cut has usually lost the cheapest part inside it, and your files are sitting untouched on a drive that never knew anything happened.
Lasswade, Bonnyrigg, Loanhead, Roslin and the surrounding Midlothian villages sit on a mix of overhead and older underground supply, and a brief outage followed by a hard reconnection is a normal part of a stormy week here. What matters is understanding which parts of a desktop are in the firing line, which are shielded behind them, and what you do in the first hour — because the damage people do themselves after the event is more often fatal to the data than the surge was.
What Actually Takes the Hit
A mains surge does not hit everything in the case equally. It arrives at the back of the power supply, and the power supply is designed to be the thing that dies. Inside it sit fuses, a metal-oxide varistor and a filter stage whose entire job is to clamp and absorb a spike before it reaches anything expensive. In the overwhelming majority of surge jobs that come across our bench, the power supply is the only failed part — the machine is dead because nothing is powering up, not because the computer inside it is broken.
Behind the power supply, the motherboard is the next most exposed part, and it is the one that occasionally goes with it. Where that happens we see it as a board that will not post, no fans, no beep, sometimes a scorch mark on the 24-pin area or a visibly bulged capacitor near the voltage regulators. Our walkthrough of the warning signs of a failing PC power supply covers the symptoms you can spot before a unit gives out completely, which is worth knowing because a lot of surge-era power supplies limp for weeks before they stop.
Storage drives sit furthest from the mains. They take a clean, regulated low-voltage feed from the power supply rather than anything resembling mains voltage, which is why a drive surviving a surge that killed the power supply is the normal outcome rather than a lucky one.
Why Your Files Are Usually Fine
The platters in a mechanical hard drive are magnetic. The NAND chips in an SSD hold charge in cells that do not need power to keep their state. Neither of them loses its contents because the mains blinked. When a drive comes out of a surge-killed desktop and goes into our bench rig, the usual result is that it mounts straight away, reads normally, and the owner’s photos are exactly where they were.
That is the bench test we do first on every one of these jobs, and we do it before we touch the rest of the machine. The drive comes out of the dead PC, goes into a known-good adapter on a test bench, and we read it there — never in the machine that just failed. Confirming the data is safe changes the whole conversation, because from that point everything else is a repair decision rather than an emergency. Our data recovery service page covers how we sequence that work, and the data recovery options for Lasswade customers page covers local collection if you would rather not carry a tower in.
The Mistake That Turns a Recoverable Drive Into a Lost One
Here is the part most general advice gets wrong. The common instinct — and most troubleshooting guides encourage it — is to keep trying the power button, swap the cable, try a different socket, maybe borrow a power supply from another machine and see if it springs to life. On a surge-damaged PC, that sequence is the single biggest risk to your files.
The reason is simple. If the power supply was damaged but not killed outright, it may still produce voltage — just not clean, regulated, in-spec voltage. A power supply whose regulation stage has been degraded can deliver a rail that drifts high, and the component least able to tolerate that is the small circuit board on the underside of your drive. Every power-on attempt is another opportunity for a compromised power supply to put something out of spec through a drive that was perfectly healthy a minute earlier.
So the bench rule we follow, and the one we would ask you to follow at home, is this: after a power cut has killed a desktop, switch it off at the wall and leave it off. One attempt to confirm it is genuinely dead is reasonable. Six are not. If it does not come on, the next step is diagnosis with the drive out of harm’s way, not another power-on.
When the Drive Itself Was Damaged
Sometimes the drive does take damage, and when it does there is a strong pattern to it: the harm is almost always on the drive’s own small controller board, not on the platters or the memory chips holding your data. On a mechanical drive you can often see it — a scorched surface-mount component or a blown TVS diode near the power connector, which is a sacrificial part doing exactly its job. The drive is dead to the PC, but the data inside it is physically intact.
That is board-level work, and it is where microsoldering and board-level repair earns its place in data recovery. Depending on what failed, the route is either repairing the damaged section of the drive’s board under the microscope, or fitting a matching donor board and transferring the original drive’s small adaptive-data ROM chip across to it — because that chip is calibrated to the specific drive and a donor board without it will not read the platters correctly. It is slow, careful work under magnification with hot air and fine-tip irons, and it is not something to attempt on a drive holding the only copy of anything.
SSDs follow the same principle with different details. The controller and its power circuitry are the vulnerable parts; the NAND holding your files generally is not. A drive that has gone completely undetected is a different problem from one that has worn out gradually, and our guide to an SSD that failed without warning goes through how we tell those two apart.
Drives That Were Mid-Write When the Lights Went Out
There is a second, gentler category worth separating out: the PC that still powers on after the outage but will not boot into Windows properly. Here the hardware is fine and the problem is logical. The machine was part way through writing something — a Windows update, a save, a file copy — when power vanished, and the file system was left inconsistent.
Windows will often repair that itself on the next boot. Where it cannot, you get a machine that boots to a recovery screen or complains that the drive needs scanning. Our advice here is firmly to resist running repair tools on a drive you have not copied yet: a repair utility works by discarding what it cannot reconcile, and anything it discards was your data. The bench order is always image first, repair the copy second. Once there is a full image, repair attempts stop being a gamble, because the original is untouched and you can try again.
Getting the Data Off, Then Deciding About the PC
Once the files are confirmed safe, the machine itself becomes a straightforward decision with no pressure attached. A dead power supply in an otherwise healthy desktop is a quick, routine replacement, and we will always say so. A board that has gone with it is a bigger judgement call: on a reasonably modern machine, board-level repair can be worth doing, while on a desktop that was already several generations old, moving your existing drive into a custom-built PC usually makes better sense than reviving a dead platform. Your Windows install and your files come across with the drive either way.
If the old tower is genuinely finished, do not put it out with the household waste. We handle IT recycling and e-waste disposal properly, and we will remove and either return or securely erase the drive first, so nothing identifiable leaves with the chassis.
And the thing worth doing before the next storm, which takes an evening: get a real backup in place. A single external drive that lives unplugged between uses, plus a cloud copy of the irreplaceable folders, means the next power cut is an inconvenience instead of a crisis. Our guide on how to back up your PC data sets out a routine that does not need much maintenance. A decent surge-protected extension block on the desk is worth having too — it will not stop a direct strike, but it absorbs the everyday spikes that wear a power supply down over years.
Bringing It In From Lasswade and Midlothian
If you are in Lasswade, Bonnyrigg, Loanhead, Roslin, Dalkeith or Penicuik and a power cut has left a desktop dead, bring it in and the first thing we will do is get your drive out and read it on the bench so you know where you stand before any repair work is discussed. If the drive turns out to need board-level attention, we will tell you plainly what is involved and what the realistic chances are rather than starting work and reporting back later. For anything urgent, the same-day repair service covering Bonnyrigg and the surrounding villages page has local turnaround details, and we collect across Midlothian if a tower is awkward to move.
Book a diagnostic online or get in touch and we will arrange a time to take a look — and if you are reading this with a dead PC in front of you, leave it switched off at the wall until we do.
Last updated: 11 October 2026