How can i prevent my PC fro..

Anti-virus and keep it up to date.

Free Security Analyizer:

http://www.microsoft.com/technet/securit...

Phishing Defense:

http://www.onguardonline.gov/phishing.ht...

Free Anti-virus:

http://free.grisoft.com/doc/1

http://www.avast.com/eng/avast_4_home.ht...

http://www.free-av.com/

http://www.trendmicro.com/hc_intro/defau...

http://www.superantispyware.com/

Other Anti-virus help:

http://www.f-secure.com/v-descs/

http://www.cert.org/other_sources/viruse...

Free Online Virus Checks:

http://onlinescan.avast.com/

http://www.avast.com/eng/avast-virus-cle...

http://housecall.trendmicro.com/

http://support.f-secure.com/enu/home/ols...

http://www.kaspersky.com/scanforvirus.ht...

http://us.mcafee.com/root/mfs/default.as...

Free Anti-Adware/Malware/Spyware protection:

http://free.grisoft.com/doc/1 I recommend ewido!!!

http://www.safer-networking.org/

http://www.download.com/Ad-Aware-SE-Pers...

http://www.microsoft.com/athome/security...

http://www.superantispyware.com/

Free Online Spyware Scan:

http://www.spywareguide.com/onlinescan.p... Very good for newbies!

You can buy Norton Antivirus.. Personally I think it's the best... But then again, you can't really prevent viruses... Unless you have a Mac.