Notebook Hardware and Upgrade Questions

I have a brand new 15.6" HP Pavillion 15-p157sa laptop running Windows 8.1, which is greaat except for the keybord issue I've been unable to solve.  Whilst typing, I'm occasionally getting double instances of the same chaaracter inputted with single key presses.

I'm having to go bacck and corrrect everything I type iin beefore I posst it.  For tthe purpose of this forum post, I'vee just left everything as it is without corrrecting the doublee letters - by way of sshowing you exacctly wwhat's happening.

My first thouught was that it's ccaused by typing too hard orr too ssoftt, so I tested that theory aandd ffoundd no change.

I then tried changging the key repeat delay settingss, but this also made no difference.

I'vve also tried ussingg the 'key bouncee' settings under acccessibilitty.  This didn't heelp either, as the fastest delay you can set it to is 0.5 seconds, sso I ended up having keey presses missed out aaltoggether, unless I slowed ddown my typing speeed.

I've searcheed the net and these forumss for a ssolution, but all I can ffind iss the isssue where people geet multiplee, different characteers appearing on scrreen, not the same characcteers doubling up, as you can see from this post.

If anyone couldd thrrow mee a bone here, I'd appreciaatee it.