Another trojan, another crash

Yesterday, I downloaded an attachment from my mail and it seems that there was a trojan attached in that mail and therefore my system crashed. Fortunately, I had a backup of all my data and therefore there wasn't a big loss. But, I wasn't lucky on the previous two occasions losing all my data a month ago. I finally realized that my AntiVirus wasn't up to the task and decided to uninstall it and install a new one. After going through hundreds of reviews I found out that CyberDefender is the best anti-virus program available in the web. They are well known for their trojan virus removal and I am sure that no trojans can enter my PC again.