viris that will not let me download

subject says it all, everything I try to download it says is harmful to my pc so it wont download at the security scan.

What OS/SP?
What exact version of avast?
Any other security(related) software installed (or did you had it installed)?
Some examples of what you are trying to download could also help.
Make sure the link(s) are not clickable.

ZeroAccess Trait… I assume you have another computer or access to one (Work, School, friend etc).

Grab a USB stick, and download FRST & aswMBR from https://forum.avast.com/index.php?topic=53253.0

Save them, throw it on the USB, plug it into your computer that’s sick and run the programs. Save the logs and attach it