@Spectacle,

Just to avoid future problems, be sure you reboot after you finished your Avast installation. Usually, it is a “must”; always recommended.

About download managers, specially for dial up connections, " FreeDownloadManager.org " (not “.com”) is free, has the checksums options, and you can configure it to scan any download with Avast too. There are other tools available; this is just one example. Download managers can usually help you with those “.72 seconds” situations you mentioned, and you can even schedule your downloads for the hours when you pay less for your dial up (or when there is less network traffic).