Let's see...
1]
I installed Avast after McAfee trial was over, which was like in the mid of summer 2015. Month or two later I witnessed my system crashed for the 1st time. Since then it has been repeating almost like on once-per-month basis
I sure would not be surprised if McAfee wasn't removed completely and is (at least) part of the problem.
2]
As I said before, there is nothing that avast does once a month unless you scheduled a monthly scan.
That is a very strong indication that it is not avast what is causing the problem.
3]
He has solved 40.000 BSOD's for people ?
Let's say he is really good.
Helping 5 people a day would mean he is doing it for about 22 years.
And 5 is already a lot.
That is if he is helping 7 days a week which is not likely.
Illness, holidays/vacation, other things to do (real life) etc...
The first BSOD's where introduced in the first Windows NT family, 22 years ago
Simple math (statistic calculations) would say that he started helping people with BSOD's over 35 years ago.
Guess what?
Not possible because they didn't existed at that time.
3]
Take your pick.
Do you want help here or at the msdn website ?