MacBook Pro won't type a lower case "X"

I have a very strange problem with my 17" MacBook Pro. The "X" key will not produce a lower case "X" in any program or font I've tried. If the cap lock key is set, it will not produce an "X", either lower case or upper case. If I press the shift key and the "X" key simultaneously, it will produce a capital "X" whether the shift key is set or not. I have tried multiple programs (mail, Word, EXcel, Power Point, Adobe Photoshop, etc.) and many, many fonts. The only way I can use an "X" in any program is to press the shift key and the "X" key, producing a capital "X". In Word, if I type something like taXes, Word will self-correct the capital "X" to a lower case "X". When typing something important, I actually have to type a capital "X" using shift, "X" and then select the "X" and change the font size for that individual letter down two steps so that it looks like a lower case "X". Needless to say, this is a tough way to type. I have also noted that pressing the alt/option key and the "X" key simultaneously will produce the eXpected ≈ symbol.

Well, I figured it must have something to do with the keyboard, so I connected an Apple Bluetooth keyboard to the computer and to my absolute amazement, the new keyboard acted eXactly the same as the keyboard on the MacBook. Now, I'm totally lost and don't know what to try neXt. As you can see, I can't type anything requiring a lower case "X".

I never knew there were so many words I use with "X"s in them.

Any help will be greatly appreciated!!