Don’t use Avast if you use an email program instead of webmail.
When Avast scans attachments, it can activate viruses in them.
Got Cryptowall that way. Avast sucks.
Put Bitdefender on after Avast failed me on my PC...4 hard drives encrypted. Ran it on my laptop and scanned the .PST file for my email program with Bitdefender and there were dozens of emailed virus attachments there.
(Used to do a lot of business with Chinese suppliers. They had a tendency to send you viruses once you stopped buying from them).
Thanks. Fortunately, I use gmail in a browser.