Update the Avast. There is no malware on your system, you can have peace of mind.

Please download DelFix by “Xplode” to your Desktop.

Run the tool and check the following boxes below;

[] Remove disinfection tools
[
] Create registry backup
[*] Purge System Restore

Now click on “Run” button. Wait for the programme completes his work.
All the tools we used should be gone.
Tool will create and open an log report (DelFix.txt)
Note: The report will also be stored on C:\DelFix.txt

I don’t need DelFix log report.

I recommended to use MCShield if you will.
You may download MCShield from one of the following links:

MyCity - Official download link
Softpedija - Mirror download link

It will prevent infection by computer via USB flash drive, mobile phone or any other memory card.
And not only will prevent infection, but it will immediately clean flash drive, memory card or external HDD.

It is a very very good program.