Angels have the Phone Box
Okay. No rush, but when you get a chance, open Defender and in the History tab, select Quarantined Items (or All Detected Items), and select to "show", widen the Detected Item column all the way to show everything, and post a screenshot of that window please.
Defender is disabled right now because Avast is on the system, so don't do this until after the Avast scan has run; you may find you have to uninstall Avast to get Defender to open up. If so, save your Avast settings so you can easily put them back when you reinstall. (I think it's Settings>General, all the way at the bottom.)
EDIT: This one, being in the temporary internet files folder, is very suspect and likely was your problem.