I rebooted but now the password key has an exclamation mark next to it. It won’t open thus I can’t enter my main Avast password
You need to have the avast master password. That is necessary to view your passwords as a security measure.
This is a link to the Avast Faq on how to reset your master password, and if that is your issue, may help:
https://www.avast.com/faq.php?article=AVKB172
I hope it helps.
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