After installing Avast on my new hard-drive I tried to enter my licence key only to receive the message “The number of successful activation’s has reached it’s limit”
How can I get my licence key reset so that I can actually USE what I have purchased?
Contact avast.
http://support.avast.com
Thank you, I have put in a ticket.
You can also try logging into Avast “My Account” and manually removing any machines on which Avast is no longer installed.
I just tried this and the whole thing is messed up.
It tells me that my licence has expired, but when I select my licences it show at the top my current running licence as active. I can find no way or option to remove machines from the account.
I think things got messed up when they changed from licence files to licence keys.
I don’t know if it will help in this case but to remove a machine, click on the “valid” license - the box will expand to reveal machines covered by the license.
Click on the one you want to remove, then “Settings” and “Delete from account”.
All that I got when clicking the licence file was my licence key and a chance to download my licence file, but now I think I have accidentally deleted my account. 
Oh, happy days.
While logged in here, open a new tab in the browser and go to https://my.avast.com
You should be logged in there.
Next click apps > devices > click on a “old” device > settings
There you will see a remove option
My old account is gone, so apart from my ticket and my order number I am lost here. From what I can see customer support is swamped with issues, so very little hope of getting any joy this side of next Christmas.
This avast has become a nightmare. Once a cool sleek virus killing machine, now a big fat greedy monster lurking inside my computer, dreaming up ways on how to ruin my day. 