PCWorld Review of Eset NOD32
looks ok for what-is-this preliminary diagnotic scans but I would want something a bit more polished to lead my onboard security team.
MBAM, SAS, and AAW: all good, and all 4 (incl Eset) are predominantly anti-spy/adware, with MBAM being the most comprehensive Anti-malware of the group.
IMHO: AVG, Avast, Avira are all good for real time protection. Avoid Norton's even though it's a good product as XP tends not to like it all that much; same for McAfee.
Make sure you have all your WIN updates (think twice about SP 3 it's improved greatly over its initial release but its not quite perfect yet, but have AT LEAST SP 2) and take Internet Explorer to Version 7 to improve surf security and system stability.
Make certain all anti-malware products (incl AV) are fully updated at least WEEKLY. Actually open the program and hit update. And if you install multiple only have one actually RUNNING in real time as they may conflict with each other. Run all the others manually (or "on demand"); like updating do it weekly if not more often.
If you get an email from an address you do not recognize just hit delete. don't even open it. (and don't use outlook, etc to retreive email as they dl infected attachments too). If the email winds up legit, the sender will ask if you got it; if it's not legit -- it's gone right? so no worries ;)
Do not click on links in email unless you are CERTAIN the sender can be trusted and that they MEANT to send you a link. Also do not download email attachments until you verify that they MEANT to send you one - a lot of bugs self replicate and spread this way.
Do not click on random pop-ups online no matter how tempting the offer...If it's too good to be true then it's probably not.
If you have an instant messenger service DO NOT respond to messages from screen names you don't recognize, and certainly do not click on any hyperlinks they message to you.
When downloading files from the internet do NOT simply hit "run". Download and SAVE (preferably to desktop for quick access) then SCAN with the anti-malware programs to be sure. once it checks out double click it to open and install.
See also: BC: The Ten Most Dangerous Things Users Do Online
and BC: How Did I Get Infected? w/tips to prevent recurrence
hope this helps! Good Luck and Safe Surfing!!