I get the wrong characters

I am using WP x5 on a Windows 7 system.  As I do my wordprocessing it almost invariably happens after a couple hours of composition and use of WordPerfect that for no known reason I get the wrong characters when I hit a key.  All of the letter seem to be quite alright and come up in either lower or upper case but many of the punctuation marks and other symbols are changed.  For example when I hit [ I get ^^ , \ comes out < and | ends up >  ; and : are okay but ' gives me `` as does " (you have to look close to see that those are the wrong characters and doubled).  My < and > give me an apostrophe and a period respectively, and / and ? give me é and É respectively. 

As you can see all the keys work correctly in this documet as they do in wordpad and Word. 

Can anyone help with this glitch?