After upgrade from 18.04 to 20.04 hypen c-haracter r ---bouncing k-ey-s

If the problem happens also in BIOS setup, then it is a hardware problem or BIOS problem and not caused by Ubuntu.

Check your hardware. Maybe there is dust under the hyphen key (or the minus key on the numeric keypad).

logging in from friends system and responding

asus sonic master Xseries i3 win8 pre installed
using since 5yrs (win8)
in between
using ubuntu18.04LTS & linuxmint 18.1 since 2yrs
all these years no problem arise few days back i think its august 01 2020 around upgraded to ubuntu 20.04
> for 3 days it worked fine.
> 3rd i connected external HDD (WD) since than the problem started
 > -------------------------------- like this the hyphen character goes on
> after typing for a while every thing deleted as if we do with backspace
> enabled bounce key options settings> accessibility > typing assist
but problem controlled a little bit but what ever is typed by me not displayed (i.e., rejected)
>to google r askubuntu i logged in linuxmint as well win8 on same machine which is in dual boot there also same problem
> enterd into BIOS to see any changes took please here every thing is like matrix jumping options when moving curosr
> even enterd into grub> thinking if i could rescue here also ----------------------- (hyphen)
> --------------------- this problem is most seen or faced with blank search, username, password, and browser address bars. pressing esc button stops and again continue
> libreo office writer i kept typing some text for while after repeated back space of this -------------- whole data is deleted

finally

using F2 enterd into win8 recovery mode managed to refresh NO change
again i entered and factory reset all data and drive NO change
entered into disk management and deleted the drives all those releated to linux drives are empty
again i refreshd but still --------------------- problem existed.

to rescue i tried to enter BIOS and grub but the system always booting directly into win8
so holding F9 enterd into win8 recovery> advanced options > uefi settings ..... from here i had to enter if i need to see BIOS after entering bios i found in primary secondry boot of linux and win still exist and some how managed to bounce/jump that cursor and made primary as ubuntu and restart laptop this time after all hardwork entered into grub> before typing its ------------------------

now again installed ubuntu 19.10 again on same partion which is 20.04 before while installing its fine but after restart entering into system again --------------------------- goes on.

what my conclusion is
format completly install linux OS's
1) but i have bio metric finger print device which presently working with win8
2) IF I format this factory installed win8 OS again i need to face trouble in situation or devices software that require / dependent on windows only
3) suppose if i managed to installed any WIN os from unknown technician or any available online free download again big head ace of that windows forfeiture. and blue screen to registar.

so let me know possible solutions.

than-k u for ur suggestion stating hardware and
https://wiki.ubuntu.com/UEFI/SecureBoot
that is the link now i m expeirmenting

apart from settings>-accessibility> typing assist
above that there is another option repeat keys disable/off that
though not solved 100% atleast in slow motion typing could help us in rectify trouble.
previously i even couldnt type password nor ls