Why is my S key intermittently typing ß inßtead of s <----See MacBook (White) 2.4Ghz Intel Core Duo, 2GB 667 MHz DDR2 SDRAM, OS X 10.6.7

Keyboard language - Canadian English (have also tried US English).  All other languages
removed, computer language ENGLISH.

All keys type fine apart from the S key which frequently types a ß or when capitalized an Í.  I am typing from a USB keyboard which types the S (s - see) fine no issues but as soon as I reach over and type on the laptop - ß there it is.

Have looked and Googled without help, I see a few others with the issue with no resolve.  Ready to throw this computer out the window!
You can check to see what OS X thinks is happening when you press the key by opening the Keyboard Viewer applet.

First, go to Language and Text in System Preferences, to enable it:


Then select 'Show Keyboard Viewer' from the Input Sources icon in the status bar.

Now, when you press the key, you can see which combination of keys OS X thinks is being pressed. You can use the keyboard viewer to enter text, too, in order to work around the problem:



You can confirm this way that it is indeed a hardware problem.