First of all Avast is free for home users...After 30 days the demo license key will expire,you can register for a new key which will last 1 year and still 100% free for home users!You must use boot scan to remove this kind of infections.That means Avast will scan before your pc is fully stared up!If you now use Avst 5 the newest one it's easy to do boot scan!Click on the Avast icon in system tray, and open Avast...So click on Boot-Time-Scan...Then click on Areas to scan, and choose all harddisks or if it's only in the system choose the system disk...Then finally click Shedule Now button, your pc will restart and Avast will scan yor hard drive and you can safly remove the infected file!

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