You press the power button, the fans spin, the motherboard logo appears, and the machine sails through its power-on self-test without a single beep or error. The hardware is clearly alive. And yet, instead of the Windows logo, you get a stubborn blinking cursor, a flat No bootable device message, or the machine drops straight into a recovery screen. This is one of the more reassuring faults to land on, because a PC that POSTs cleanly and lets you into BIOS has, by definition, working RAM, a working CPU, and a board that is doing its job. What has failed sits one layer up: the software that tells the machine where Windows lives and how to start it.
In other words, this is a bootloader problem, not a hardware problem, and it is almost always fixable without spending a naira on parts. The repair centres on the Windows Recovery Environment and rebuilding the boot files. If your symptom is different — the drive itself has vanished from BIOS or you see an INACCESSIBLE BOOT DEVICE stop code — read our guide to an inaccessible boot device instead, and for the broader checklist start with troubleshooting a PC that will not boot.
First, Confirm the Drive Is Seen in BIOS
Before you touch anything, enter BIOS (tap Delete or F2 as the machine starts) and look at the storage or boot devices list. This single check splits the whole problem in two. If your Windows drive — the NVMe SSD or SATA drive Windows is installed on — appears in the list, you have a software or bootloader fault, and everything below applies to you. If the drive does not appear at all, that is a hardware branch: a dead drive, a loose cable, or a failing controller, and our inaccessible boot device walkthrough covers that path.
Assuming the drive is visible, set it as the first boot device while you are in BIOS. It is surprisingly common for a BIOS update, a CMOS reset after a power cut, or a newly added drive to shuffle the boot order so the machine tries to boot from the wrong device. Save, exit, and try again — sometimes that alone brings Windows back.
Boot the Windows Recovery Environment
If correcting the boot order did not help, you need to get into the Windows Recovery Environment, the toolkit that repairs a broken Windows installation from outside it. The cleanest way is a Windows install USB, which you can make on any working PC using Microsoft's Media Creation Tool onto an 8GB or larger flash drive. Boot the faulty machine from that USB:
- Insert the USB and select it from the boot menu (usually F11 or F12 at startup).
- At the first Windows Setup screen, choose your language, then click Repair your computer in the bottom-left corner — not Install.
- Navigate to Troubleshoot, where you will find Startup Repair and the Command Prompt.
Keep that USB. A Windows install stick is the single most useful tool a Nigerian PC owner can keep in a drawer, and it costs nothing but a spare flash drive.
Run Startup Repair First
From the Troubleshoot menu, run Startup Repair before anything else. It is automated, low-risk, and it silently fixes a large share of boot faults — missing boot entries, minor bootloader corruption, and a misconfigured Boot Configuration Data store. Let it run fully, even if it sits for several minutes, then restart and remove the USB. If Windows loads, you are done. If Startup Repair reports it could not fix the problem, do not panic; it simply means the damage is deeper than the automatic tool handles, and the manual rebuild below is the next step.
Rebuild the BCD and Boot Files
When Startup Repair gives up, the manual repair from the recovery Command Prompt is the reliable fix. Open Command Prompt from the Troubleshoot menu and work through the standard bootrec sequence, which repairs the Boot Configuration Data — the small database that points the firmware at Windows:
- Type bootrec /fixmbr and press Enter — this repairs the master boot record.
- Type bootrec /fixboot — this writes a fresh boot sector.
- Type bootrec /scanos — this scans the drive for Windows installations.
- Type bootrec /rebuildbcd — this rebuilds the boot configuration and adds Windows back to the boot menu.
Most modern PCs built in the last several years use UEFI with a GPT-partitioned drive. On those systems the boot files live on a small EFI System Partition, and if that partition is the part that got corrupted, the fix is to rebuild it with bcdboot — for example, pointing bcdboot at your Windows folder (commonly C:\Windows) so it writes fresh EFI boot files. This is the modern equivalent of the bootrec sequence and resolves the majority of UEFI boot failures where the drive is healthy but Windows will not start.
Check for a UEFI versus Legacy Mismatch
There is one trap that catches people after a BIOS reset or a CMOS battery change: a mismatch between how the BIOS is set to boot and how Windows was actually installed. Windows installed in UEFI mode onto a GPT drive will simply refuse to start if the BIOS has switched to Legacy or CSM mode, and vice versa. The machine still POSTs perfectly, which is why this is so easy to miss.
Go back into BIOS, find the boot mode setting, and make sure it matches your installation — for a recent build that almost always means UEFI enabled and CSM disabled. After a power cut wiped your BIOS settings to default, this single toggle is a common reason a previously healthy PC suddenly will not boot. If your machine instead hangs at the board logo and never reaches Windows at all, our guide to a PC stuck on the motherboard logo covers that specific symptom.
Repair Corrupt System Files, Then Suspect the Drive
If the boot files are rebuilt but Windows still stumbles, corrupt system files may be the culprit. From the recovery Command Prompt you can run SFC and DISM in their offline forms — pointing SFC at your offline Windows installation and using DISM to repair the component store against your drive rather than the running system. This catches damage that the bootloader repair cannot reach.
If, after all of this, the drive keeps re-corrupting itself, throws errors during these tools, or disappears intermittently from BIOS, the drive itself is probably failing. At that point the priority shifts from repair to rescue: get your data off it and onto a healthy drive. Our notes on how to tell a hard drive is failing help you confirm it, and our migrating Windows to a new NVMe clone walkthrough shows you how to move your installation onto a fresh SSD.
Frequently Asked Questions
My PC was fine until a power cut during a Windows update — is that the cause? Almost certainly, yes. A power cut mid-update is the single leading cause of a corrupt bootloader in Nigeria. The update was halfway through rewriting boot files when the power dropped, leaving them in an inconsistent state. The good news is that Startup Repair or the BCD rebuild above fixes the overwhelming majority of these cases, so work through those steps with confidence.
Will any of these steps erase my files? No. Startup Repair, the bootrec and bcdboot commands, and offline SFC and DISM all repair the boot and system files only — they do not touch your documents, photos, or installed programmes. The one thing to avoid is choosing Reset or Clean Install from the recovery menu, which is a different option that does wipe data. Stick to the repair tools described here.
How do I stop this from happening again? Fit a UPS. Because the leading trigger is a power cut interrupting Windows while it writes to the drive, a UPS that holds the machine up long enough to shut down cleanly removes the risk almost entirely. Our guide to a PC that will not boot after a power cut goes into the power-quality side in more depth.
The One Thing to Remember
If your PC POSTs cleanly and lets you into BIOS but Windows will not load, you are looking at a software fault, not dead hardware — and that is good news. Confirm the drive is seen, fix the boot order, then let the Windows Recovery Environment do its work: Startup Repair first, then rebuild the BCD or EFI boot files, then check your UEFI versus Legacy mode. The hardware that survived POST is almost always fine; it is the signpost to Windows that needs rewriting, and that is a repair, not a replacement.
If you would rather not crawl through recovery menus during a downpour and a power cut, we can help. Tell us your symptoms through our contact page and we will talk you through it, or if it is time for a more dependable, UPS-backed machine, design one to suit your needs and your budget with our configurator.