It sounds like you may be using an incorrect IME (input method editor) for your locale. Here is Microsoft's official page on the subject:http://windows.microsoft.com/en-us/windows-8/input-method-editors-windows-8
My recommendation is, while on the desktop, look in the system notification area, near the bottom right hand corner of your screen, where the clock is usually located. Next to the clock should be an abbreviation for the language and layout type that is currently active. You can click on the input method icon to bring up the options available to you. You can add and remove IMEs as you need and switch between them using the Windows Logo Key + Spacebar.
Hopefully this helps. :-)