Hi, thank you for the information. I don't have any other Avast software, to the best of my knowledge I have never downloaded any (possibly some slipped by in another download?). The problem seems to have arisen around the time I downloaded an Office suite, but I have since removed that and there is no trace of it on my computer, yet the Avast files remain. I can't download a screen shot of Avast Secureline updater running in task manager right now because it only happens occasionally (but when my computer begins to freeze and become unusable it is invariably there). I will attach a screenshot of the Avast Secureline folder that remains in my files. The orange blob icon beside "Secureline VPN updater" is, I believe, what also appears in task manager.
I have added a screen shot of the start up tab from my task manager as I just realized Avast SecureLine always shows there.