Hi Neelie and congrats on sorting this out.
Security is something we all strive for and in my opinion, you can't have to much of.
Having more than ONE Firewall will cause them to conflict with each other and will actually be less secure. As long as you have one Good Firewall, all of the other security measures you take will only Help keep you relatively safe. Having several different security programs or utilities is most important as each program will catch things that the other might miss.
Be sure to have a Good Firewall and Anti-Virus program in addition to what ever other security programs you choose.
Hope this Helps.
