Just as a little footnote to this. We've had a mega virus problem on our computer. Neither Malwarebytes nor AVG could sort it.
(
The virus had blocked any updates from Microsoft and anywhere else, so AVG didn't know about that type of virus? (Ouch! My brain hurts.)
Anyhoo... we now have 'avast!' anti-virus - also free - and it's been brill so far. Touchwood...
God I HATE computers!!!!