WTF ..... is happening with this program that it's locking me out of the internet?

Having just upgraded the hard drive in my computer (W10) I’ve reinstalled a free copy of AVG.
The AVG own web browser is not accessing the internet at all
" This site can’t be reached
The webpage at https://google.com/ might be temporarily down or it may have moved permanently to a new web address"
With Waterfox it’s only accessing half of the sites that I use. Even my own websites are blocked from me And … even AVG’s own site is blocked
" This site can’t provide a secure connection
platform.avg.com sent an invalid response."
On Chrome half the sites are blocked, the other half work (up to now, anyway)
The only browser that seems to access everything is Tor.
When I’ve come to log in with my account on Chrome, with the details that AVG automatically inputs when you type in your username, it tells me
“access denied. Too many users on this account” even though I’m the only person who lives here and the only one who ever uses this computer and i.d.
So what’s going on?

Further to the above -
I uninstalled AVG this morning and my computer went back to working quite normally.
I installed an anti-virus from “a competitor” and there were no issues at all subsequently.
There is, therefore, every reason to suppose that it’s the AVG anti-virus that’s been causing all these problems and in the absence of any kind of reply at all to my message above to help me resolve the issue, then I’m sorry to say that AVG has been “filed under CS”, as anyone who has ever watched “American Graffiti” will immediately understand