everyone you ask will have their own favorites to suggest:  for mine, see posts 2,3,4 and 5 here:

http://www.dellcommunity.com/supportforums/board/message?board.id=si_virus&thread.id=67004

(Kaspersky is probably a better choice than McAfee -- referred to in the other thread -- but the same advice still applies)

Hi

You can use free security software.

Free Anti-Virus Programs

AVG Free Version
http://free.grisoft.com/freeweb.php/doc/2/

avast! antivirus 4 Home Edition
http://www.avast.com/eng/avast_4_home.html

Avira AntiVir® PersonalEdition Classic
http://www.free-av.com/

ClamWin Free Antivirus
http://www.clamwin.com/

Free Anti-Spyware Programs

AVG Anti-Spyware (Free and Paid Versions)
http://www.ewido.net/en/download/

Malwarebytes' Anti-Malware (Free and Paid Versions)
http://www.besttechie.net/tools/mbam-setup.exe
http://www.majorgeeks.com/Malwarebytes_Anti-Malware_d5756.html

Spybot Search and Destroy (Free)
http://www.safer-networking.org/en/download/index.html

SpywareBlaster
http://www.javacoolsoftware.com/spywareblaster.html
This will block bad ActiveX and harmful cookies from getting on to your PC in the first place. Just download and install the program. Open SpywareBlaster, check for and download updates, then 'select all' to protect against all items checked. Program needs to be kept updated.

Super AntiSpyware (Free and Paid Versions)
http://www.superantispyware.com/http://
http://www.softpedia.com/get/Internet/Popup-Ad-Spyware-Blockers/SUPERAntiSpyware.shtml

Free Firewalls (Free and Paid versions available)

Comodo Firewall
http://www.personalfirewall.comodo.com/overview.html

ZoneAlarm
http://www.zonealarm.com/store/content/company/products/znalm/freeDownload.jsp?dc=12bms&ctry=US&lang=en

From Chris

My computer
Dell Dimension 1100
Microsoft Windows XP Home SP 2
512 MB of Ram
Nvidia Geforce FX 5200 256MB
Intel Celeron CPU 2.53GHz
Dell E196FP
HDD WDC WD800BB-75JCO 80GB C:
HDD Samsung SV2042H 20GB F:
TSSTcorp CDRWDVD TS-H492C D:
LITE-ON DVDRW LDW-851S E:
Linksys Wireless-G WUSB54GS With SpeedBooster
Logitech Cordless Desktop EX 90
Logitech Cordless Click Plus Rechargeable Optical Mouse
Logitech QuickCam Pro 5000
Mozilla Firefox 2.0.0.13
Internet Explorer 8 Beta 1

My Security Software
Avanquest SystemSuite 8 Professional
Windows Defender

Hi

I used Avanquest SystemSuite 8 Professional.

:smileyvery-happy: 

From Chris

My computer
Dell Dimension 1100
Microsoft Windows XP Home SP 2
512 MB of Ram
Nvidia Geforce FX 5200 256MB
Intel Celeron CPU 2.53GHz
Dell E196FP
HDD WDC WD800BB-75JCO 80GB C:
HDD Samsung SV2042H 20GB F:
TSSTcorp CDRWDVD TS-H492C D:
LITE-ON DVDRW LDW-851S E:
Linksys Wireless-G WUSB54GS With SpeedBooster
Logitech Cordless Desktop EX 90
Logitech Cordless Click Plus Rechargeable Optical Mouse
Logitech QuickCam Pro 5000
Mozilla Firefox 2.0.0.13
Internet Explorer 8 Beta 1

My Security Software
Avanquest SystemSuite 8 Professional
Windows Defender

To ky331, thanks for the link to other thread and the advice much apreciated.

To helmecj01, thanks for all those recomentions and links will check all of those out much apreciate the help and advice on getting the right security software.

To europa303, I just installed a 60 day trial of Kaspersky Internet Security 7 on my current system and think so far its pretty good however I do have one problem thats slight doing my head in and thats all web links in Outlook 2003 are now blocked and clicking on any just causes Outlook to freeze was fine prior. Any sugestions as to what to do to stop it?

I'm going to suggest you post on the Kaspersky forum for expert help there.  I have not observed your situation.

http://forum.kaspersky.com/index.php?s=e753826758770a5e23a4ec4d25dac334&showforum=4