[SOLVED] Does my faulty laptop keyboard need cleaning or replacing?

[AnotherPCuser]

I bought a used/"second-hand" HP Elitebook 8470p in May last year. The keyboard, a US qwerty keyboard (which didn't look like the original, looks more like it's a replacement, as it didn't have the pointing stick common in most HP elitebooks) worked just fine until last January, when the right alt-key got stuck. Navigating the pc got very hard and the key only got briefly unstuck after pressing the start button. I tried to clean underneath the right alt key in case there's any dust or crumbs but that didn't work. I downloaded a program named KeyTweak to disable that key to get rid of that problem for good. A few months later, though, the f4 key got stuck in the same way, so I disabled that key too. And then the page down key got stuck that way. And today the L key got stuck. Yikes, I don't wanna disable a letter key! Typing would get so much of harder.

The issue isn't just that keys get stuck. Sometimes another key gets typed together when I type a shift character, the extra character depending on which shift key is pressed. RShift+2 types 'W@' and LShift+2 types 'X@'. RShift+9 gets 'O(' and LShift+9 gets '>(' . This applies to quite a few keys. A bit annoying but bearable as I can backspace them out.

Recently, a few weeks ago, came another very odd issue. When I click the space bar while caps lock is on, multiple other keys are also triggered by it. These are the keys pressed according to keyboardchecker.com.
https://drive.google.com/file/d/1gyVrptdnt4VD1u3FoUUCrnOmxwT7EFtH/view
(Please click on the link for the image, as I couldn't insert a google drive image on here for some reason.)
Note: Caps lock is not green as it was already turned on before I went to the website. The dash/underscore key is also pressed but appears grey instead of green for some reason. The fn key and the key to the right of f12 are not pressed.

So, when I click the space bar when caps lock is on, loads of weird stuff happens. When I'm using a browser, the window goes fullscreen, the webpage gets zoomed out, any message or email typed gets sent prematurely, and it gets hard to navigate around until caps lock is off.

Thankfully, these issues aren't present when I'm using an external keyboard.

Some specs of my laptop: (Please do ask if you need more)
HP Elitebook 8470p
Windows 10 64-bit
Intel i7-3740QM 2.70 GHz
Intel HD Graphics 4000
US qwerty keyboard, and the keyboard layout in settings is also set as US qwerty

My laptop keyboard uses a standard microsoft ps/2 keyboard driver from 2006. I couldn't find any new drivers for the keyboard on HP's driver websites and uninstalling the device and driver on Device Manager doesn't help either. The external USB keyboard I used seems to use the same driver but it works just fine.

Today I decided to clean underneath some of my problematic keys (caps lock, spacebar, f4, L and page down) and I detached the keyboard from my laptop, following a YouTube tutorial, and I dusted off the flat surface underneath where the keyboard is (with some dry tissue) as it was dusty, and wiped my keyboard with some cloth and tissue. I attached the keyboard again and I tested my keyboard, the issue seemed to be resolved for a short while but came back when I enabled the keys I previously disabled. The page down key and L key don't get stuck anymore though, for now. Phew. Just the right alt key and the f4 key remain stuck, which I disabled again.

I learnt that some of the reasons why keyboards get faulty are because of dust, or worse, motherboard issues. I do sometimes eat snacks and biscuits/cookies while using my laptop. If I clean my keyboard, I guess I should clean underneath every key just in case, but that would be time-consuming and possibly risky as I don't have the most delicate of fingers. But maybe the problem is that the keyboard is too faulty and I need to replace it. So I'd like to hear some opinions from you guys. Should I clean it or should I go ahead and replace the keyboard? (And if that doesn't work, I'll just contact my computer guy.)

Thank you all so much in advance for your responses. I'm awfully sorry for the long post and I'm very sorry if I'm my post is incoherent and riddled with grammatical errors. English is not my first language. I also apologise to moderators for the frequent edits, it's a bad habit of mine on forums when I make long posts

 

[AnotherPCuser]

Thank you moderators for moving my topic to the correct subforum!

UPDATE: Today I tried to clean the whole keyboard. I literally opened every key's cap and tried to dust the keys with a dry unused watercolour paint brush and I even used a very soft vacuum cleaner on them. I detached the keyboard and brushed and vacuumed underneath it as well. Everything looked very clean when I was done. Most of the dust was on the keys near the laptop cooler fan, like backspace, enter and the "| \" key. Interesting that those keys actually still worked before this despite the loads of dust underneath them. I also took the advantage to clean the cooler fan while I was at it.

When I click the space bar while caps lock is on, multiple other keys are also triggered by it.

So after cleaning it, it looks like the Caps lock/spacebar issue is gone for now, thank goodness. I hope it stays that way.

The right alt key and f4 key, unfortunately, are still stuck when enabling them so I disabled them again.

The issue isn't just that keys get stuck. Sometimes another key gets typed together when I type a shift character, the extra character depending on which shift key is pressed. RShift+2 types 'W@' and LShift+2 types 'X@'. RShift+9 gets 'O(' and LShift+9 gets '>(' . This applies to quite a few keys. A bit annoying but bearable as I can backspace them out.

This issue is still here too, without any improvement.

Right now I'm confused. I guess cleaning works, as the caps lock/spacebar issue is gone, but I guess didn't clean my keyboard correctly, so other the other keyboard issues gained no improvements?

I didn't remove the plastic thing underneath each key that attaches the key cover to the keyboard button, because if I did that it would then probably take an extra hour or two to remove them all and attach them again, ugh. Some websites also recommend using a cotton bud/q-tip with alcohol applied on it, but some others discourage that (I don't have any alcohol swabs with me anyway). I also don't have a compressed air can, which is why I used a soft vacuum cleaner instead.

So, what do you guys think? Do you guys think that I should try cleaning it again or do you think the keyboard is just faulty and I should buy a replacement? I did find a very affordable replacement keyboard online, but I am worried that the issue might be a motherboard one, and that would mean I wasted my money on a keyboard and I have to then send my laptop to repair with my computer repair guy. So, I would really like to hear your opinion(s).

 

[AnotherPCuser]

So after cleaning it, it looks like the Caps lock/spacebar issue is gone for now, thank goodness. I hope it stays that way.

Looks like this issue came back the next day after posting this.

But the good news is, I ordered an affordable replacement keyboard, I got it about 2 days ago, replaced my old keyboard for it and it works just fine. I believe my old keyboard got faulty due to laptop heat. My room at home is air-conditioned, but my university hostel room isn't, and it's also quite stuffy.

My laptop did begin to get faulty when I was in the hostel too, and the Caps lock/spacebar issue only came back after I was using my laptop for long hours, so I indeed think it's heat that made my old keyboard faulty.