Hello sirMAXX and welcome to the forum.
Since you have Windows 7 as your OS, you can stay with the
Windows 7 firewall (FW), which will provide you with excellent protection.
As for adding other layers of protection, I suggest the following as previously mentioned:
-
MBAM (Malwarebytes):
http://www.malwarebytes.org/ - either free (on-demand) or Pro (one time paid for resident protection)
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CCleaner: a free system optimization, privacy and cleaning tool. There is a
Slim version available as well at
http://www.piriform.com/ccleaner/builds – scroll down. It removes unused files (cache, temporary Internet files, etc.) from your system, allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. There is no need for another registry cleaner to bog down your machine.
Additionally, you do not need a defrag with Windows 7, but if you really want one, Puran is a great tool since is also does a regular defrag as well as a boot-time defrag
http://www.puransoftware.com/.
You do not need HitmanPro since this is now considered outdated according to our malware removal experts who use other tools like OTS. Others may disagree with me, but I assist enough with malware removal, and this is just my opinion.
You should be fine with the bolded tools above in addition to Avast. Enjoy your new machine. Let us know if you have any other additional questions.