Hi Filip Severs,
Do you know the path of the infected file? When did avast! alert you to the file (e.g was it after an update, after you downloaded a file, etc...)?
First check if it is a false positive at VirusTotal
). See how many scanners detect it.
If a majority
of the scanners detect it, try and do a boot-time scan
with avast!... Here is a website which tells you how : http://www.digitalred.com/avast-boot-time.php
Have it run and hopefully it'll get rid of it... Bear in mind the scan will take some time, unless you specify the folder/file you need to scan (e.g. in Step 5 on that website instead of choosing "Scan all local disks"
choose "Scan selected path
and browse to the folder which has the infected file in...).
If it is a false positive
then add it to the Exclusions List
1. Right click on the avast! icon in the system tray and select On-Access Protection Control
2. Open the Standard Shield
screen and click on the Customize
button on the right you may need to click on Details...>>
to see this
3. Click on the Advanced
tab then Add
and enter the path of the file in.