AVG is from the Czech Republic, capital Prague, a small and efficient antivirus program, from http://free.grisoft.com
In my opinion, this beats the pants of current incarnations of Norton Anti virus and McAffee which used to be the de facto standard for PC protection but have become bloated and, due to their remaining prevalence, now a prime target of anything that does manage to get by,
AVG has no firewall, because I find XP's own firewall more than adequate.
AVG has no Anti-spam because your Internet Provider should be taking all reasonable measures to defeat spam. What they cannot stop, your machine will certainly have trouble with,
Stick to the Ant Spam tools within a decent EMail program like ThunderBird which relies on your address book to figure who you do or do not communicate with,
The site above also inludes a link to New AVG Anti-Spyware. Spyware is a different kind fo threat handled differently that viruses and worms, but just as important. Windows Defender, provided by Microsoft, has been found largely ineffective even against fairly well known threats.
The above AVG programs are free for personal use, and have limitations such as Support that do NOT impact their efectiveness. KVMR has used a site license for all its computers since 2005.