FREE SOFTWARES FOR PC

I have gone through the experience of becoming familiar with the use of computer being a Surgeon.Hope that my experience of managing it with free software might help others to begin using PC. FREE antivirus products are AVIRA,AVG,AVASTI,PCTOOLS and ClamWin and all these are good.Cleaners of PC are Ccleaner,Fcleaner,COMODO and Iobit Systemcare.Malware guards and cleaners are NORMAN(Very good),Lovasoft,Spybot Search and Destroy and Spyware Terminator.Pc optimisers from COMODO is good.Update manager of Filehippo is good.Some free software download sites are Filehippo.Softpedia ,Iobit and Cnetdownload center.Google also provides some uility software package . Mozilla provides Firefox(Very good) browser ,Thunderbird E-Mail client and many other .
Wish a good start.