Trojan Horses are viruses that infect your computer and open backdoors
for more infections to gain access. Once you have a Trojan, you can bet
on having a few more things. Once AVG has put it in the virus vault,
you shouldn't have anymore problems out of that file. Now if you get
infected again from somewhere on the net, then you will have to let AVG
handle it again. AVG free has always been good for me. I have used it
for about 5 years now. It seems to be pretty efficient at finding and
taking care of infections. Always remember though, there is no 100%
method of keeping infections out. New viruses are created every day to
exploit a plethora of flaws in software. Be careful about what you are
downloading. Make sure it is from a trusted site. If you aren't sure,
then don't download from that site. I hope this has helped you.