Some users may tend to go for pirated versions of Norton/Mcafee but most of these cracked/hacked versions of these antivirus softwares themselves have spywares built in with them.So it is always safe to download these tools from their respective websites.
1.AVG ( http://www.grisoft.com )
AVG Free edition is one of the widely used free antivirus tool, it provides almost all features of paid versions. AVG free edition has real time protection,automatic updates, full system scan and scanning selected areas of your computer. It also has email scanninga and scanning inside compressed files.The only difference from professional edition of AVG is the cuctomer care support, otherwise there is no difference in the service.This is fully functional software unlike most trial softwares, and the software is valid as long as you wish to have it.
Other notable Antivirus softwares include :
2.Free Avast! 4 Home Edition (http://www.avast.com/eng/avast_4_home.html)
3.If interested checkout some of other antivirus partners for Windows who offer free trials from 90 days to 1 year.
Antispyware Tools :
1. Windows Defender : It is the most(more than 25 million users) used free antispyware tool from Microsoft, It offers full real time protection, anti spyware scans and also automatic updates every day.
2. Ad-Aware SE Professional : This is one of the widely used anti-spyware tools minus real time protection, this is serious disadvantage otherwise Ad-Aware works just fine.
3. Ewido anti spyware : Same as Ad-Aware , but gives a 30 day trial of its auto-protect option.
Zone Alarm is the widely used free firewall. It provides all basic features of any paid verion of firewalls.
For any info mail me email@example.com K J Dinesh