My keyboard has suddenly started behaving erratically after years of working normally. Sometimes a key gets held down and produces results like "iiiiiiiiiiiiiiiiissueeeeeeeeees," while other times the first word or two I type does not register at all. The same delay affects games: in Project Zomboid, movement can continue for a moment after I release a key, which makes stopping dangerous.
The problem happens unpredictably during ordinary computer use, and I haven't found a reliable way to trigger it. I'm using a NuPhy Air96 V2 keyboard and a Logitech MX Master 3S mouse. I cleaned the keyboard, moved the wireless dongle between USB ports, tried Bluetooth, updated the keyboard and dongle drivers, ran Malwarebytes and Microsoft Defender scans, and restarted the computer several times. None of that has clearly fixed it.
Windows Update also reports that my Western Digital NVMe hardware isn't ready for the current version of Windows, although I'm not sure whether that is related. I'd appreciate suggestions for diagnosing whether this is the keyboard, wireless connection, USB controller, BIOS, storage hardware, or Windows itself.
2 Answers
Try a full power cycle and test several USB ports, including both front and rear ports. Shut the PC down, disconnect the keyboard for a few seconds, reconnect it, and boot back up. A failing USB port or controller can cause dropped or delayed input, and ports on the same machine don’t always fail together.
Try another keyboard even if it’s only borrowed temporarily. That’s a much more useful test than reinstalling Windows right away. If both keyboards show the same delayed or stuck input, then investigate the USB controller, motherboard drivers, BIOS, background software, or system performance. A BIOS update may be worth checking after confirming the exact motherboard model and following the manufacturer’s instructions.

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