The PC does not complete hardware startup
No normal lights, fans, vendor logo or display? Check power, connections, display, memory and other hardware first.
Windows recovery: start with the failure you can see
Start with the last stage the PC reaches and choose the matching guide. A machine that does not power on, one showing No boot device, and one that crashes after the Windows logo need different checks.
Lees in het Nederlands →- 1HardwareNo POST or display
- 2SSD / bootNo boot device
- 3Windows logoHangs or restarts
- 4UpdateProblem afterwards
- 5Offline repairInstallation reachable
Choose where startup stops
The SSD is missing or you see ‘No boot device’
Check that the SSD is detected consistently in UEFI, the computer’s settings before Windows starts.
- If the drive is missing or appears only intermittently, stop Windows repair and protect the data first.
- If Windows is still present but Windows Boot Manager is missing or the boot configuration is damaged, continue with:
The Windows logo appears but startup does not finish
Start with the built-in recovery options: Startup Repair, removal of a recent quality update where relevant, System Restore and Safe Mode. The guide below explains when to try each and what its result tells you.
The problem started directly after Windows Update
Check whether the update completed or stopped during installation.
- A completed quality update that causes problems can often be rolled back first.
- An interrupted update may require package-state or component repair before more packages are removed.
A cumulative update did not finish
If package state and logs point to an interrupted update and rollback does not restore a healthy previous state, check that the official package matches the Windows release, processor architecture and build, and that any required earlier checkpoint updates are present before applying it offline.
Windows will not run but the installation is accessible
Offline repair means working on the installed copy of Windows while it is not running. Windows Recovery Environment (WinRE) and Windows PE provide an environment for this; drive letters there can differ from normal Windows.
DISM checks and repairs the installed Windows image and its component store, the collection of Windows components used for repairs. SFC checks protected system files against that store.
Stop code 0xC000021A
0xC000021A means Windows cannot continue because a critical process has terminated. The code does not identify one file, driver or update by itself.
Before following a manual repair guide
1. Find the real Windows volume
diskpart
list volume
exit
dir C:\Windows
dir D:\Windows
dir E:\Windows
Use only a volume containing Windows, Program Files and Users. Do not assume Windows is still C: in recovery.
2. Check BitLocker
BitLocker encrypts the Windows volume. Check whether it is locked before trying to access the installation:
manage-bde -status
Do not change boot or partition settings while the Windows volume is locked and the recovery key is unavailable.
3. Watch the SSD
Stop if the drive disappears, reports I/O errors or becomes extremely slow during simple reads. Protect the data first.
Stop if
- you cannot identify the Windows installation or partition confidently;
- important data has no usable backup;
- BitLocker cannot be unlocked;
- the SSD shows signs of failure;
- an update package cannot be matched exactly to the installed Windows version;
- previous changes cannot be reconstructed;
- malware has compromised trust in the existing installation.
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