Wi-Fi Code 43 applies to the adapter shown in Device Manager; it does not mean the router or Windows Update is definitely at fault.
Protect your files first
Back up important files when possible. If the drive is encrypted, locate the BitLocker recovery key before recovery changes. Stop if storage appears to be failing or this is a work or school managed PC.
What to record
Exact adapter and PC model, driver version, whether other devices connect, and any managed-network policy.
The exact message, Windows version, and whether the desktop still opens matter more than a guess based on the symptom name.
Try these safer checks
Check the adapter status and compare the driver to the PC maker’s official package. Test whether other devices have the same network problem before changing Windows.
Change one thing at a time. After each check, see whether the same symptom returns and write down what changed.
When to stop and get help
On work or school laptops, ask IT before changing network or security controls.
If this is a work or school device, contact its administrator before changing managed settings.
Keep track of your checks
This checklist stays in this browser session. It is not sent to WinErrors.