Aaah, another one who hasn't read the rules...
What must we do to make people read them?
Anyway, it's possible that you have the multilingual version and something happened and the language setting changed to a language that uses different characters, apparently not supported by your PC (for example, Japanese, Arabic...)
If that's the case, launch LW and go to the second or third tab, select the last option and choose the language. Something like this: