A computer virus or spilled liquid that damages internal circuits sometimes causes the keyboard to type the wrong letters, but a more likely explanation is that the computer's input language has been changed. The input language is the language that the keyboard types in.
To identify which issue is causing the problem, users should try the following troubleshooting tips. If an individual has a spare keyboard, he should use it to test if the current keyboard is damaged from a spill or accident. This involves connecting the spare keyboard to the computer. If the problem resolves, then the current keyboard's internal circuits are damaged. If the spare keyboard also types the wrong letters, then the cause is either the input language or a virus. Next, bring up the computer's input language. For Windows 8, Microsoft instructs users to click on "Settings," then click on "Change PC Settings." Users then select "Time and Language," then click "Region and Language." Users then select "Options" to view the language settings that are currently selected. If a keyboard language is listed that is unwanted, users can select it and click "Remove." For Mac users, Apple instructs users to click on the Apple menu, then select "System Preferences." Users then click "Keyboard" and select "Input Sources." Users can then check the list of languages for any that are unwanted and de-select the box beside it. If changing the input language does not fix the problem, then a virus is the most likely remaining cause. Users can scan their computer for viruses using the preferred virus software, or they take the computer to a repair shop.