hp 50g keyboard problem

[samo50g]

i am not an expert but long time ago i solved non-responsive key on my recently passed 28S. I used contact cleaner in spray. It is meant for cleaning contacts in electronic devices. It evaporates in several minutes. Just spray it into any opening around the button. However, do it on your own risk, please.

However, mu theory about bad contact is not supported by what you wrote. getting letter X instead of Y shows that button it works however in a wrong way.
Honestly, I think you cannot lose much if you use contact cleaner spray. wait 15 minutes or more after spraying the button.