Antivirus software

there are a lot of virus software around - including some free ones

there are free programs available for example AVG from
www.grisoft.com or AVAST from www.avast.com

have a look here

How did I get infected in the first place
http://forums.techguy.org/t208517.html

Security Help Tools- this has a full list of software available
http://forums.techguy.org/t110854.html

I think you will find lots of different reviews for these programs, so as to which one is best i don't know - i have used avg, avast and norton
I'm sure someone with experience of McAFEE will reply

as far as combination - only have one virus software on PC at any one time.

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AS FAR AS THE REST GO
heres some info

How did I get infected in the first place
http://forums.techguy.org/t208517.html

Security Help Tools- this has a full list of software available
http://forums.techguy.org/t110854.html

1) Install anti virus software
there are free programs available for example AVG from
www.grisoft.com or AVAST from www.avast.com

2)XP has a firewall already
available - to activate it
ON your PC
start>
connect to>
right click on your connection to broadband (this may be lan or usb)
properties>
advanced>
tick the box - internet connection

see tutorial here
http://www.practicallynetworked.com/sharing/xp/ic_firewall.htm

But i suggest also a separate piece of software for a firewall
one of the following two free programs are good

Sygate:
http://www.homenethelp.com/web/howto/free-firewall.asp

Zone labs:
http://download.zonelabs.com/bin/free/download/index2_11072.html

Tutorial on Firewalls
http://www.bleepingcomputer.com/forums/tutorial60.html

3) spyware
All these programs must be updated before you run them.

I suggest four programs to control spyware (all free)
two programs you run to remove the spyware and the other two stop
spyware getting onto the PC in the first place

a) Spybot search and destroy - because these sites are attacked to
stop them providing this solution, I have a few sites to get the
software

http://spybot.safer-networking.de/
http://tomcoyote.org/SPYBOThttp://www.download.com/3000-8022-10122137.html
http://www.spybot.us/spybotsd13.exe
http://www.safer-networking.org/
http://www.thewhities.com/

b) Ad-aware - because these sites are attacked to stop them providing
this solution, I have a few sites to get the software

http://www.lavasoftusa.com/
http://www.networkingfiles.com/Cookie/adaware.htm
http://www.lavasoftusa.com/support/download/
http://www.thewhities.com/

The next two try to protect the PC from getting infected in the first place
c) Spywareguard
http://www.javacoolsoftware.com/sgdownload.html

d) Spywareblaster
http://www.javacoolsoftware.com/spywareblaster.html

Tutorials for the above

AD-Aware:
http://www.bleepingcomputer.com/forums/index.php?showtutorial=48
http://www.dotcomsecurity.org/forum/viewtopic.php?t=4

SPYBOT:
http://www.bleepingcomputer.com/forums/index.php?showtutorial=43
http://www.dotcomsecurity.org/forum/viewtopic.php?t=25

SPYWAREBLASTER:
http://www.bleepingcomputer.com/forums/index.php?showtutorial=49
http://www.dotcomsecurity.org/forum/viewtopic.php?t=43

SPYWAREGUARD:
http://www.bleepingcomputer.com/forums/index.php?showtutorial=50
http://www.dotcomsecurity.org/forum/viewtopic.php?t=44