Its usually best to download/install your Antivirus program as soon as you are done doing your clean re-install and then immediately after that download /install your windows updates!
A clean system can be infected within seconds after going online without the proper antivirus/spyware/malware protection.
For free Antivirus go here: http://free.avg.com/download-avg-anti-virus-free-edition
or here: http://www.comodo.com/products/free-products.php
Both are free and well respected.
Go here for antispyware (SpywareBlaster) http://www.javacoolsoftware.com/sbdownload.html
AND Here: http://www.safer-networking.org/en/index.html
(Spybot Search and Destroy)
Both are free and are well respected.
And go here for Anti Malware: http://download.cnet.com/Malwarebytes-Anti...&tag=button
(AntiMalwareBytes) also free and all of these programs work on my machines without conflict.
These programs are free and will get you on the way to keeping your machine clean.
If you find you are already infected then go here: http://www.bleepingcomputer.com/tutorials/simple-steps-for-removing-malware/
for a Bleepingcomputer Tutorial for removing Crap from your confuser.
BTW: you only want to run one firewall and one antivirus program. The other programs I have linked to all run well together on my machines.
Hope this helps!
Edited by ranger72, 02 September 2009 - 03:31 PM.