Hi Wildchild. sorry I've been out to lunch or would have responded earlier. Yr post came in as I was bout to post, but I have sent this off anyway.
What tech says is correct, if repair is not go well this time then outcome can be disaster for you. That is why the action to fix will come with warnings. Personally, I will say now that it is not worth to run fixmbr. To have run fixmbr with fixboot as I said as a general optimise would have been to instate your default Windows boot functions as clean running (as day they were born). This is why I do it as general optimise.
I thought - perhaps with boot all back to default, and clean, maybe boot-time scan would run ok or maybe action would prompt message to screen when runs first time through new boot. Even though unlikely that you have boot problem - you are booting through okay to Windows environment both with user account and Administrator, which pretty much says all. And like Tech says there is definite element of danger when repairing where boot problems. More than that, Tech is very experienced with avast program and is familiar with the many particulars (or peculiarities for avast unique type functions) that come with the running of the program. His advice is good.