|You could download a PuppyLinux iso and burn it to a blank cd or dvd. Then run it without installing it (Live).|
Boot from the iso image and you will be able to delete any nasty .inf files etc from the pen drives and pc.
NOTE: Check all pendrives, Ext HDD etc that have been on this pc.
Then look at something like Autorun Eater to block any infected pendrives from your pc.
Here's a great tool for taking control of your pc. WinPatrol free:
And I suggest leaving Avast free as your main Antivirus and Malwarebytes free as your 2nd on demand malware scanner. (You should uninstall all other Antivirus programs as the realtime scanners in each, will cause conflicts.)
Next run the Eset online scanner (Tick Scan Archives) include the log it makes in your next reply. (It takes a while to run)
Please reply and let us know if our help worked. Your feedback helps others. Maybe you?