I don't think you understood my post
I said sometimes because of the software you are FORCED to run (such as SAP etc in a corporate / business environment - so no user choice normally) you HAVE to have older versions installed in this case it was the JRE 1.4.xx version).
My point was that IF you are forced to use older versions the AV software is not always reliable in doing its reporting - and even with newer stuff you can still get a load of false positives.
1) If ANYTHING is reported as a "positive" always check from another "reliable" source (that begs the question as well --what is a "reliable source") what the offending program / module / .dll etc is.
2) Check again with at least one (preferably 2) different AV software systems.
Before even THINKING of installing AV software you should get up to speed on some of the methods of computer protection and how these are implemented so you can make a sensible choice.
Start first by reading some fairly non technical info such as this AntiVirus Software Review 2009 - TopTenREVIEWS
You'll find NONE will ever be 100% effective but at least know what you are up against.
Cheap or FREE is not necessarilly bad - converse is also true Expensive is not necessarily good either.
Here's a review of the FREE one's Antivirus Software Review: Free Antivirus Software
At the current state of the art I tend to think the disadvantages of AV software far outweigh the advantages of using it -- but that's MY opinion and I don't d/l music / films / multi-media etc from dubious sites and am usually pretty careful in how I use computers -- browsers and web based email tend to be the most common method of infection and then these are transmitted to other machines often by the use of USB devices.
Usually it's people trying to install dubious software or load those HORRIBLE sneakware programs that offer to find drivers
, fix your registry etc etc whilst you are online that are the major cause of "contaminants".
I've been using PC's since the late 70's and have NEVER had a virus / trojan on my OWN machines.
Some work machines I've had problems with and these are often large companies who can afford (and do) spend loads and loads of money on this -- and they STILL get problems.