For the past 3-4 years I have been recommending Windows XP users to install a small combo of basic applications that will grant a more secure and thus stable experience with the OS.
Nowadays SP2/Windows Defender should be a given and along with it you should install a good non-bloated anti-virus like AVG or AntiVir (both free), a good software firewall like ZoneAlarm, and a couple of trusted anti-spyware apps to run at least once a month. Everyone’s favorites seem to be the free Adaware and Spybot.
If you are familiar with all of those and you don’t rely on any untrusted sites, you should be in pretty good shape. Now I have another one to add to your list if you want to keep your system as secure as possible and rootkit-free. So, what are rootkits?
Rootkits are a specific type of malware which hide in other applications or a computerâ€˜s operating system kernel. They allow malicious applications to collect passwords and sensitive data from the infected computer without the userâ€™s knowledge, this can be used for personal information theft, spam relay and other criminal activities.
From the programs I just mentioned above, the anti-viruses should help a bit but none are specialized in detecting this kind of malware.
There used to be a pretty good free scanner from F-secure but the utility is no longer available. But don’t worry, AVG has got you covered with their Anti-rootkit Free utility, download that here and add it to your list of important programs.