Macbook pro typing random symbols instead of alphabets!!

I am using a mid 2012 Macbook Pro (13 inch) running on OS X Yosemite (10.10.5).

I am having an issue with the laptop keyboard that types random symbols instead of alphabets.

When I try typing 'qwertyuiop' I get 'œ∑´®†¥¨ˆøπ'.

When I use another external keyboard is when I am able to use the laptop normally.

I tried reseting the PRAM (Command + Option + P + R) and reinstalling the OS (Command + Option + R), but get stuck in entering Wifi pw as no characters get recognised (Both Laptop keyboard and external keyboard).

I tried using the keyboard viewer and still end up with the same result.

I found out that there is a difference in the onscreen keyboard when i type in the laptop keyboard and the external keyboard.

Laptop Keyboard : The on screen keyboard has the qwerty keypad with all the numbers on top of the qwerty row. But clicking on the keys is displaying symbols only. 

External Keyboard : The on screen keyboard has the qwerty keyboard with numbers on the side (like a windows keyboard). Clicking on the keys is displaying the alphabets correctly.

PLease help!