Help wanted: Specific keys not working: 1, 2, 3, 4, p, backspace

After a long 11+ years of Ubuntu, openSuse, Windows 10 mixed usage, I got attracted to "elementary OS". Hence installed it on my laptop. Was working fine for first few days.

Day by day I started noticing that the numeric keys on top "1" through "4", the alphabet key "p" and the "backspace" keys were out of normal working.
Not that they never worked. They go out of working intermittently.
Suddenly works when, on certain times, I hardly press them (this I really do not understand).
I tried changing the input methods, regional settings, keyboard settings, etc. Opened the laptop and cleaned the keyboard inner area. Nothing seems to be solving this difficulty.
Even typing this question took me 16 minutes (I counted it).
If someone could solve this impediment, I will thank them by recording their name in my local contact store.

Please help & thanks in advance.