Common reasons exist as to why what you type on your PC keyboard may not correspond with what appears on the screen. Your keyboard language settings may be incorrectly configured, or you may have inadvertently switched on a "number lock" feature on the keyboard.
As computers are sold all over the world, there are many different keyboard configurations, which include different accented letters and currency symbols. Computer operating systems can be configured to use various different regional keyboards. If your keyboard isn't typing the correct letters or symbols, it may have been incorrectly set to the wrong keyboard layout.
Computer operating systems including Microsoft Windows and Apple Macintosh OS X allow you to change your keyboard settings. Verify that your settings match the keyboard you are using.
A common reason for this problem on laptop keyboards is that the laptop keyboard has been set to number lock mode. Most laptops allow you to switch an area to the right of the keyboard into a different input mode in order to quickly enter numbers. If some letter keys are producing numbers on-screen, check to see if your number lock feature is active. This is often controlled via one of the function keys, and there may be an indicator light on the laptop.