I use NOD32.It works very well against trojan.U may try it.
This program provides automatic Internet/network update of key system elements including the executables and virus signature databases (a valid username & password is required).

There's no antivirus that can protect against all virus or trojans or adware or spyware, beleave it.

I tryed many antivirus, firewalls, and all that BS, and noone of them protect you against all malware, none.

If you cought a trojan, and you can't heal, just delete it, and if you can't delete it, reiniciate your pc, and perhaps your antivirus will be able to resolve the situation.

Do not change antivirus, avg is very good, i use the pro version right now, is is better, but it can defend agist the same amount of virus, and i never catch a trojan because i also use a firewall with strict rules, so get a firewall too, antivirus can't protect against all trojans, but firewalls can because they supervise all ports, and if the ports are closed, trojans servers can not connect to the trojans clients.

Another thing you can do is to go for a online free antivirus scan, trend micro and others offer this for free, and you should do it to check if your antivirus is actually functioning correctly.

Test your antivirus, test it with the eicar.com code, it's a sort of virtual virus that check if your antivirus can protect you against the execution of virus code.
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When avg moves a file to the valut, you do not have to worry about it, it's the quarentine, but if you want to delete it, just go to the virus vault and select it to delete, or delete the entire virus vault.