Hewlett Packard keyboard problem-

Its a mystery.....I have a 3 yr. old Hewlett Packard HP Pavillion computer. About 2 weeks ago, my keys on my keyboard got replaced by some other wierd key letters. I have searched my computer for hours to try to resolve this. Had a friend come over and try too.
Rather than get an apostrophe for the apostophe key, now I get this ÈÈÈÈÈ and for the small slash under it that I am suppose to get, I get this èèèèèè

and my question mark is gone up to my upper case number 6 key.
My question mark key now is now this ÉÉÉÉ and my slash is this éééééé.

Can anyone tell me how to reconfigure the keys back to the way they are suppose to be???
I need these keys to write essays for English class, like the apostrophe.
thanks a bunch for help...