1. check out firetune software for a quick safe firefox optimization -->
http://www.totalidea.com/product.php?Product=FireTuneadblock plus and ie tab are good extensions to have on your firefox (you can find them on the official firefox addon page)
2. I would use commodo firewall as my firewall (it's free and always will be) over the windows firewall, you should disable windows firewall first to prevent any potential firewall conflicts.
3. grab avg, avast or avira antivirus program (they're all free and only one is needed. don't get more than one but get the one you like best)
4. Have Ccleaner, Malwarebytes antimalware and superantispyware and perhaps advanced systemcare on hand.
That's all I have on mind ... I'm sure you're already familiar with a lot of this stuff I mention and oh yeah, use the windows diskcleaner to clean out old restore points as they take up space.