Starting a New Computer. What protection do you recommend

Good day. I've just finished reinstalling Windows XP sp3 on my Dell. I had a virus or something that I couldn't get rid of. What protection (I like the free kind) would you suggest to install and why? In the past I have used AVG, Adaware, Spybot, Advance windows care, CCleaner and Malwarebytes. I'm sure some of these overlap in protection and I'm not too sure if I have the correct protection or what they do or don't do. Not sure how firewalls work and maybe I'm running two of them? Like LT Schultz, I know nothing!
Expertise and actual help are greatly appreciated.
Thanks,
Dan F

 

I also have windows xp sp3 and only use the following on my computers. This first 2 are mix and match (you can use different brands software) returnil and commodo are the last line of defense type software. I wouldn't surf the internet without having at least returnil or comodo to fall back on.

1. zone alarm firewall (make sure you disable windows built-in firewall). The firewall prevents programs that are on your computer from calling out, example if a trojan is in your computer it will try to access the internet to send out you data. A firewall will alert that you might have a spy in your computer. It will also block other computers on the internet from connecting to your computer.
2. avira free antivirus (faster and less bloated than avg)
3. firefox browser 3.5 only (very resistant to getting compromised)
4. returnil (free version) I use this instead of antispyware software, when enabled it seperates the hard drive from the internet, no known/unknown virus/spyware will defeat this software.

Another program more powerful than returnil (cannot be installed together) is comodo time machine (freeware). You can installed this on a clean computer and it will make a baseline snapshot. Before you go on the internet you can create a new snapshot (takes 3 seconds), if you run into problems/malware just restore your computer to this snapshot. It's similar to windows system restore but much more powerful especially against bad drivers/software/malware.
http://www.brighthub.com/computing/smb-security/reviews/61309.aspx

Finally use a free imaging software (macrium reflect) to make an image backup of your c: drive while it's clean. Worst case scenario you can restore your computer to a like new windows condition without spending hours reinstalling windows.