Keyboard problems can be confusing because they do not always look like hardware problems. A shortcut may fail in one app, a key may repeat in a text field, or a letter may stop appearing only sometimes. The first step is to separate the keyboard from the application. A keyboard test online can help because it shows whether the browser detects each key press. Press the keys that seem unreliable and watch the feedback. If the test detects the key consistently, the issue may be app-specific. It could be a shortcut conflict, input method setting, browser extension, remote desktop session, or software focus problem. If the test does not detect the key, or detects it inconsistently, the issue may be closer to the hardware or operating system. Common causes include dust, liquid damage, a loose external keyboard connection, low battery, Bluetooth interference, or a damaged switch. Testing every key is also useful after spills, repairs, travel, or switching keyboards.…