I tried to do a boot scan but I get a message that Avast can not do a boot scan on a 64 bit system
you need V5.1 or later to do 64bit bootscan

Try this

Malwarebytes Anti-Malware 1.50.1 http://filehippo.com/download_malwarebytes_anti_malware/
always update so you have latest database before you scan
click the remove selected button to quarantine anything found

post the scan log here