When downloading files from the internet, Avast (and other antivirus software like AVG) might block the downloads marking them as infected by DRep. The message is a bit misleading because DRep is not a virus infection but rather a preventive downloading blockage. Read here how to fix it.
General support quesions
A picture is worth 1000 words, they say.
If you see something is wrong with the screensaver, press the "Print Screen" button on the keyboard.
This is a special key that puts a copy of the screen in the clipboard without stopping the screensaver.
Do not try to get a screenshot with the mouse since the mouse movement would stop the screensaver.