first documented computer bug
https://www.nationalgeographic.org/thisday/sep9/worlds-first-computer-bug/

IIRC the term "bug" to refer to a problem predates the existence of digital electronic computers.
note: use of "digital" and "electronics" is to make sure that I'm referring to an an apparatus that is digital (rather than analog) and electronic (rather than mechanical) and to make sure that I'm not referring to a person (i.e. usage of term "computer" to refer to an occupation).
What computers at JPL looked back in the 1940s and 19502: https://www.nasa.gov/mission_pages/explorer/computers.html

>Back to the original definition of "debug" :)
>
>>I've taken to occasionally "gravity-clean" keyboard (invert keyboard, then shake vigorously while changing its orientation in various directions, as well as returning it upright to let any debris that gets caught in the keycaps while inverted) -- also run a narrow brush between the gaps as well -- indeed it's amazing the amount of debris that sometimes comes out. I also have a narrow brush that I use to help loosen some stuff. On one occasion I've found a dead bug.
>>
>>>Usually a hacker will take pains to hide their activity, what you describe doesn't sound like hacking to me. My first guess would be a problem with the keyboard, especially if an external USB one works properly.
>>>
>>>You might have a stuck key - try hitting every key at least 4 - 5 times and check none are sticking.
>>>
>>>Has the keyboard ever had anything heavy dropped on it, or liquid spilled on it?
>>>
>>>You could try gravity-cleaning it:
>>>
>>>- put down a sheet of paper to catch debris
>>>- turn your laptop upside down over the paper and hit it lightly in different places across the back/under the keyboard, 20 - 30 times
>>>- you may be amazed at what falls out - I've seen staples, paper clips, lots of food particles. Those can jam the key mechanisms, cause short circuits etc.
>>>
>>>You can also try a can of compressed air, but if you do that I recommend doing it upside down as well so debris isn't driven further into the keyboard mechanism.
>>>
>>>Dells usually have built-in hardware diagnostics you can access during a cold boot.
>>>
>>>>>https://answers.microsoft.com/en-us/windows/forum/windows_10-other_settings-winpc/cannot-login-my-windows-10-computer-cause-the/ab1b3b6c-bfcd-49f9-b16d-762a47959e22
>>>>>
>>>>
>>>>I read a few of these but this is not my situation.
>>>>
>>>>I use PIN number to open Windows on that laptop. If I put external keyboard, I can type and login and I was even able to do one Zoom class. I used different social media (not a FB) to communicate with one fellow instructor who gave me that link. I left computer and that other social media open for ~5 min. and then I returned I found that one character letter started appearing on its own again in that window as well. After that I shut down that laptop again and not doing the class which I wanted to do. I believe it's a clear indication of hacking :( I also closed all browser windows, but I'm not sure how much information was already gathered.