|Be a bit careful.|
LSASS.EXE is a genuine Windows file and should not be removed, see description in response #1.
ISASS.EXE is a Virus. It is so named to make you think it is a genuine file - see below.
When they are in lower case they look identical. See where the file appears in the alphabetical list of files and look in Properties for info. While you are there you could Copy the name from the General tab (Ctrl+C) then paste it into NotePad. The difference between "L" and "I" is obvious there because of the font used.
No harm running MalwareBytes, whatever your situation.
Just found this
Always pop back and let us know the outcome - thanks