So here is a short version of the long story:
dropped my computer
needed new hard drive
never got around to getting anti-virus software
So I got Avast again and every time I open Firefox and then sometimes randomly while I’m browsing a little “BING BING BING BING Threat has been detected” comes up. The Domain is always different but it always ends in “/sync2/?q=hfZ9ofD5hchEAen0rjaErjaFtMqLDe49CNU0llrMCMlNhd9Fqja9rjgFrTa4rTsMBzqUojw8rdnFqTw6qjYHqSh7hfs0pihPBMn0rjnFqjn9rjaFrTY6pdsHqHgFqjYMC6qUojn8rTn9rdYEpjC8pjYHrdn6qjrMWy4ZBek0D6ZwB6DKBy0ZhchOAen0qjs6rTrHrdg7rjs7pda4qdC5tMl5Aen0rTw9qHn5rHg9qGhLC7VUojgErihPBNq9ojsHtMtHojw%3D&atmp=0”
I’ve seen other people with this same problem on the forum, but the responses always say like “CAUTION THIS WONT WORK ON YOUR COMPUTER” so yeah.
Thank you for any help
Hi monkeysrool75, welcome to the forum 
Please follow this turtorial https://forum.avast.com/index.php?topic=53253.0
Than start a new topc here https://forum.avast.com/index.php?board=4.0 and attach the requested logs.
As soon as an expert is online and available he/she will help you.
Greetz, Red.