The missing file belongs to Avast, so if you have removed Avast :cry: then you dont need it, and it will be back if you remove NOD32 :slight_smile: and reinstall Avast :smiley:

http://forum.avast.com/index.php?topic=17121.0

And yes multi Anti virus or firewall is no no. When necessary, you can always get another opinion by performing an online scan
Recomended to have is MBAM http://www.malwarebytes.org/