Do you have an anti-virus programme Michael...like AVG or Avast ? (these are totally free to download and use).

Do you have a 'malware' detector and destroyer, like 'Malwarebites' (also free)?

First thing I would do is run both of these progs and see what they reveal.

I have had this desktop pc for 11 years and have managed to sort out all sorts of odd behaviour on it.