Macbook Pro: CAPS always on, Backspace key not working: Faulty Keyboard?

Do I have a faulty keyboard or a Firmware / OS problem?

Apologies for long post, but I want to clarify all I have attempted and to point out some doubts.

Macbook Pro Mid 2010 Intel OSX 10.11.4 I know there is a free update, will sort later.

Note I have done a lot of online searching before posting here.

To clarify symptoms:

1. When Macbook starts all keys return CAPS, numeric keys return !"£$% etc -- CAPS button light turns off and on when pressed, but no difference in characters typed
2. Backspace key does not delete

All other keys seem to be OK

Disabling Caps Lock key via Preferences / Keyboard has no effect on fixed keyboard, but does affect external USB keyboard.

Firstly a big thanks to @Monomeeth and @n1000 for helping me to reset password to use CAPS and to reset SMC and NVRAM in my previous question.

First important point is that an external windows keyboard works OK. That points to to a faulty fixed keyboard - but read on.

To clarify how I used the windows keys as alternative to Mac keys for resetting SMC and NVRAM Option = Alt Control = Ctrl Command = Windows Key

Is the keyboard really faulty, or is there some hardware reset still to do or not done correctly? Does the Firmware / OS have the same affect on fixed and external keyboards?

Here is why I am not convinced I have a faulty fixed keyboard (though I may well be wrong). a. below is my main reason for doubt

1. It is likely that my Caps key is not faulty, as the led turns on and off Therefore it is "appears" one of the shift keys is 'stuck' on - keys physically move OK, -- but of course there could be some foreign body making one of the keys act as if it is pressed. -- or could there be a firmware or software issue that makes the shift key 'appear' to be stuck ON?
2. The other 'faulty' key is the backspace key. All other keys appear to be OK -- Is it likely that only the Shift key and the backspace key developed a fault at the same time - one sticks ON and the other does not work? -- probably could only due to a liquid spill - which my daughter would deny

Why do I think the Shift key is NOT physically stuck ON or on due to a foreign body?

I try a SMC reset 2 different ways: Battery not fully charged Magsafe light is Amber

a. -- Using built in keyboard - Hold Down (ONLY) Option & Control + Power for 4 seconds and let go. -- Amber Magsafe light never changes color -- Mac starts normally -- If the Shift key is stuck, then I would expect the same as occurs with b. below b. Same as a. above but ALSO hold the Shift key -- Magsafe light turns green for about 5 seconds -- Mac does not start until I press Power or re-try a. above

This suggests to me that there is not a physical problem with the shift key

Now - things that cause more questions:

1. Repeating B above on external windows keyboard (Shift, Alt (Option) Ctrl) starts the Mac normally, no green light on Mag Cable Maybe SMC reset can only be done from the fixed keyboard?

2. Have I reset SMC correctly? The change of Magsafe light from Amber to green sould suggest it has worked his page would seem to agree (bottom) https://discussions.apple.com/thread/7633757 -- But when fully charged the Magsafe light always stays green during the SMC reset

3. Have I reset nvram correctly? No timing combinations of Shift, Option, Control and Power will cause the mac to resrart twice Always starts with the recovery screen -- Tried both keyboards (note caps lock on fixed keyboard probably prevents nvram reset from working) -- Tried holding Shift, Option, Control and Power before pressing power and immediately afterwrds + multiple timing variations of this.

So how did I clear NVRAM (and did I) - Thanks to @n1000

With the exernal keyboard and a normal startup Reset NVRAM via Terminal with the command nvram -c

Did that actually reset NVRAM? No other text displayed in Terminal after nvram -c - so I assume command was accepted. I double checked with nvram -xp This displayed a list of 8 to 10 parameters, all end with = and nothing else, so I presume all are empty

So back to my original question, do I have a faulty keyboard (one shift key stuck on and one backspace key not working)?

I have not tried to remove keyboard or keys.

Any suggestions would be appreciated.

1. Go to System Preferences > Keyboard
2. Check the box Show keyboard and emoji viewers in menu bar
3. In the menu bar click Show keyboard viewer

This will show you which keys are being pressed and will hopefully help you to answer your question...