I foolishly downloaded an innocent looking pool game, and now I'm pretty certain this is how my P.C. has been infected by a malware program called pixel.mathtag - I won't complete the full web address, just in case!
My internet banking account was deleted, (I assume it was the malware's doing!) and I presume that the motive was to get me to re-apply and register new password etc., thereby enabling the phishing to succeed.
Time to format & reinstall everything, because I can't get it eradicated by other methods. See you all on the other side!