"a" or "if" is typing itself into a Word of Excell document

[Ronnie]

I thought I had a virus, but the scans are negative.
When I am in either Word or Excell, the computer starts
typing words by itself...... "a", or "if", or "half".
Then if I go to save the document, the name of the
document changes to "a".

What is wrong? How do I fix it?

Thank you.

Ronnie