Unknown things happening whilst writing an email/ and also audio interjection.

[Mokurai]

I have been having a problem with someone/thing appearing to be trying to contact me frequently but no indication who from ...HP, Norton, or Microsoft ...I keep getting these continual ding ding dong ...ding ding dong etc.  If they want to make contact why not simply email me as there is nothing to show who it is; the other thing some weeks ago I was writing an email and all of a sudden my writing went spastic and sent a whole lot of iPiPiPip taking over my email. I then had Norton do every virus check they had including a Deep Check and everything was said to be clear of a virus of any kind. After that it seemed to come right but this morning I had it come back whilst writing an email; this time it took over using the i9ji9ji9ji9ji9ji9j. Now makes me wonder if the first time was i9i9i9i instead of P. Do not know if this is a product that uses those letters/numbers to denote what it is but I do not like it taking over ALL my emails, one after the other. 

Appreciate any and all suggests how I can kill there two things. I know how to eliminate the ding ding dong simply by turning the sound off my computer, but I noted yesterday when I gave HP a checkup and had left the sound off that it spotted it was off and turned it on to 50%. After that the ding ding dong returned. Thanks for any help you can give me. Wonder where you guys are as my content was last autosaved at 2246 whilst it is 1447 here in Victoria Australia. 

[Prométhée]

Hello
there is not too many experts in virus problems here, it seems to me
If you receive a "ding ding dong" notification, I suppose that it is the windows notifications that should be deactivated for the mails
open windows settings, click system, then notifications
go down to mail, and click on it
you can either deactivate everything, or simply deactivate "make a sound on reception"
I think you won't be bothered by the sound at least
Now check carefully, in your mail, you must have information about the sender, if there is nothing clear, it is probably SPAm, do not click the links, do not respond!
However, I did not understand what you are saying
"trying to contact me frequently but no indication who from ... HP, Norton, or Microsoft ... I keep getting these continual ding ding dong ... ding ding dong etc. If they want to make contact why not simply email me as there is nothing to show who it is "

Maybe you don't receive an email and what you hear is something else.
"this time it took over using the i9ji9ji9ji9ji9ji9j. Now makes me wonder if the first time was i9i9i9i instead of P."

have you tried with something other than email, does the problem happen with something else, or is it just in email that it happens?
for this problem apart from a keyboard problem i don't see much, i never heard that we could have fun, modifying your emails like that!

[WAWood]

@Mokurai 

Malware infections can take LOTS of different forms including notifications, popups and audio alarms.  There are too many different ones for us here to be able to diagnose or repair any of them.

They also have the ability to HIDE themselves from antivirus products, so even running something like Norton is no guarantee that your PC is not infected.

The only SURE way to remove such infections is to do a completely clean reinstallation of your PC -- and to do that, you need HP Recovery Media.  You should back off all your personal data to USB sticks before you do this, as you will lose everything in the process.

If your PC is a 2016 model or newer, you should see if you can make a bootable USB recovery drive using the HP cloud recovery tool on a working PC.

The recovery drive can then be used to install Win10 and the HP drivers and utilities that originally came with your PC.

Here is the link: https://support.hp.com/us-en/document/c06162205