Solution Steps

1. Check physical connections: USB cable, wireless dongle, batteries.
2. Restart computer.
3. Update keyboard drivers: Device Manager → Keyboards → Update driver.
4. Test keyboard in different USB port or on different computer.
5. Clean keyboard: Remove debris and compressed air.
6. Check for stuck keys or physical damage.
7. For wireless: Re-pair keyboard or replace batteries.
8. Try on-screen keyboard: Windows key → Type "On-Screen Keyboard" or System Settings → Accessibility → Keyboard (Mac).