Thanks again Paul. Yes, I agree regarding fresh Windows 10 install.
I have backed up all my files, and made a System Image back-up. All malware has now been removed, so I may make a fresh System Image backup (took 4 hours the last time).
Although the un-installation of Office 365 appeared to be stuck on stage 1 of 4 (overnight), I don't see it listed in installed programs any more. Through my college Outlook account (and My Account), I am presently re-installing Office 365, though it has been "stuck" at around the 95% mark for the past hour (the first 95% took about an hour). I will be patient though.
Task Manager, Processes shows MS Windows Search Filter Host and MS Windows Search Indexer as the top two CPU processes (Search Protocol Host is up there too), while Firefox (32 bit), MS Windows Search Indexer and Service Host Local System (Network Restricted) (9) as the top three Memory processes.





I have traced the product key for Office Home and Student 2010 and a receipt (and On the Hub link) for the upgrade to Office Pro Plus 2010, so I should be okay to re-install.