My computer repeatedly types the letter "C" and sometimes behaves as though the Ctrl key is being held down. I unplugged my keyboard, reinstalled the keyboard drivers, and even factory-reset the PC, but the problem keeps returning. Pressing Ctrl sometimes stops the Ctrl-like behavior and causes the C key to start spamming instead. What could be causing this, and how can I troubleshoot it?
3 Answers
Turn off Bluetooth completely and check whether another paired keyboard, controller, or other device is sending phantom inputs. Also inspect Task Manager for macro tools, auto-clickers, or key-remapping software. If the behavior continues with all peripherals disconnected and Bluetooth disabled, test the PC with a different keyboard or have the motherboard and USB ports checked.
The fact that pressing Ctrl changes the behavior suggests that some device may be sending stuck or alternating key signals. A second hidden keyboard, wireless dongle, controller, or faulty USB device could do this. Unplug USB and PS/2 devices one by one rather than only removing the main keyboard, and make sure no receiver is still connected.
Since the issue continued after a factory reset and with the keyboard unplugged, this is probably being caused by another input device or a hardware problem rather than Windows or the keyboard drivers. Disconnect every peripheral except the monitor, including game controllers, drawing tablets, wireless receivers, USB hubs, and anything connected through Bluetooth. Reconnect them one at a time to find the culprit.
It happens even after I unplug the keyboard, and I already reset the computer, so I’ll try disconnecting every other device and disabling Bluetooth next.