Though this log is devoted to market, I think this post will help a lot of traders safegurad their pc.
Keep the following with your for great performace and safety.
1. Firewall is a must and i trust Zone Alarm free
Use of Firewall is first defense. Like keep home clean.
2. Antivirus I trust Avg Antivirus Free
You can also try Anti-Vir Free
3. Spyware remover. In case you get spies in ur comp.
Especially if you use comp to acess online accounts.
I trust Ad-Aware Personal
Also try WindowsDefender 2 (you need authentic Windows license for this)
Some more alternates are
Now this is just my small list.
If you love some other stuff do let us all know.
Drop a link in the comments of this post.