I really appreciate your help everyone. Not had a chance to read through every comment yet, will do when I have more time.
My bank very recently changed their online system. They still support XP and I'm very glad that Avast does also.
That's great bob3160 about those SP4 updates, Eddy previously mentioned those. "Avast also comes with SafeZone Browser which protects you while doing your Banking and Shopping." That's reassuring to know.
Perhaps I should, as you suggested, contact Avast directly. Don't want a messed up uninstall.
I think Avast Clear could do it though?
Thank you for the compliment CraigB.
Having a working computer means so much to me. I'm very interested in computers and security too, have an inquisitive mind, which helps.