yes, there are free antivirus which is recommended here often
what windows version do you have - you may not need a firewall
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i'm not an expert here - but if you look through the security forum, you will see a lot of recommendations for windows 7/vista
The windows 7/vista firewall is considered adequate and especially if you are connected behind a router.
Have a read in our "general security" forum and look for the advice from our security gurus.
Several excellent free antivirus programs are available (But you should only ever have 1 on the PC at a time otherwise this can cause issues ).
Microsoft Security Essentials (MSE) I personally use and install in the computers that I work on.
http://www.microsoft.com/en-gb/security_essentials/default.aspx
If you are using windows 8 - you already have this product and its now called windows defender (different to the earlier windows versions, also known as "windows defender")
Avast
http://www.avast.com/free-antivirus-download
AntiVir
http://majorgeeks.com/Avira_AntiVir_Personal_-_FREE_Antivirus_d955.html
EST Nod 32 also gets a lot of very good reviews although it is not free
ESET NOD32
http://www.eset.com/home/
these Two programs are also recommended to be on the PC and can be on with any of the above antivirus programs.
Malwarebytes I personally use and install in the computers that I work on.
http://www.malwarebytes.org/mbam.php
superantispyware I personally use and install in the computers that I work on.
http://www.superantispyware.com/download.html
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