avibky: I recommend you to stay with BitDefender Antivirus as its detection rate is much more better than those most common used Antivirus softwares. The system resources required is higher but it is worthwhile since it really protects your pc and keeps it in utmost and maximum safety and security. But you have to install Firewall as well which you can try your luck to take part in niroop giveaway on Online Armor Personal Firewall.