I'AM NEW OPERATING A COMPUTER, I DO NOT HAVE A ANTI-VIRUS PROGRAM, BUT LOOKING FOR A GOOD ONE THAT DOES NOT SLOW DOWN MY COMPUTER. ANY COMMENTS ON THESE ?..."THE SHIELD DELUXE" [29.99] OR "AVIRA ANTIVIR PERSONAL EDITION-FREE," OR "AVAST HOME EDITION -FREE"....I HAVE WINDOWS XP PROFESSIONAL, SP2...451MHZ AND 384MB OF RAM, PENTIUM 3... I RECENTLY DOWNLOADED WINDOWS DEFENDER, AND IT HAS STOP THE POPUP ADDS THAT I WAS HAVING TROUBLE WITH... WOULD ANY OF THE ABOVE ANTI-VIRUS PROGRAMS INTERFERE THE WIN. DEFENDER I HAVE?..OR MY WINDOWS PROGRAMS???...ANY REPLY WOULD BE OF HELP. TKS......