Keyboard issue - my late 2010 MBP was working fine until SUDDENLY none of my letters would work - just numbers and a few other keys, and my trackpad would not left click, every click and tap was registered as a right click.

Question

If I reboot, my mouse functions normally UNTIL I hit any of the keyboard keys, then it wont stop right clicking everytime I click.
Some of my keys are acting wierdly - I think 'I' does the TAB function, and J for example acts as the Enter/Return key.
I have opened the keyboard utility thing, and it recognises that I am pressing the keys, but nothing is being typed on my screen.
I have attempted to boot into safe mode, reset PRAM, run AHT but my Macbook simply doesnt want to know, just boots into OS X normally - this is with the built in keyboard and a USB External One.
Its worth noting also that with the USB keyboard, I can type fine - also, if I reboot, my clicks are fine until I hit a key on the inbuilt keyboard, then it starts its right clicking again, however, if I then press a key on the USB keyboard the trackpad is 'reset' and allows me to click normally again.
I have read various other threads but none really the same as mine which *****.

Answer 1

Shut down the computer.
Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer. 
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
ALSO if the computer turns on, the reset was done incorrectly