Some years ago I was provided with a computer running CA eTrust antivirus. Having been alerted that the antivirus software was no longer current, presumably because the subscription has expired. I decided to uninstall CA eTrust and install McAfee Virus Scan. However, even after uninstalling eTrust the McAfee product refused to install as it detected a remaining component of eTrust on the computer. Furthermore, even after obtaining technical support from both CA and McAfee I have been unable to install McAfee Anti Virus. As such, I have now sought a refund from McAfee. However, there is now no antivirus protection on the computer. What should I do?

You definitely need to have antivirus software installed on your computer, so for the moment I would recommend that you install AVG Free (www.avg.com.au) on the computer. As you would have read in a previous question in this column, AVG Free provides you with relatively basic antivirus protection. While AVG is a sound product, I would recommend that you look at commercial antivirus products for the longer-term. As you have discovered, some of these products are refusing to load onto your computer. Therefore, I would suggest that you load a trial version of the antivirus software onto your computer before future purchases to ensure it works and that you are satisfied with the product.

A commercial antivirus product that I would recommend is ESET NOD32 Antivirus (eset.com.au). This is a very good antivirus product and you can download a 30-day trial from their website. The aspect which I most like about this product is the low-footprint on your system. Unlike other bloated antivirus products which slow down the system, NOD32 is lean on resources and thus I have found does not unduly slow down the computer or hog resources. Additionally, the price of the product is competitive with the price of other antivirus products. Another alternative you can investigate is AVG Anti-Virus or AVG Internet Security (www.avg.com.au). While I have not used these products I have read good things and they also come from the same software company as AVG Free which is a good free antivirus alternative.

If you find that these products also refuse to load onto the computer, or they do not work properly due to the remnants of CA eTrust on the machine, then I would say this is a good indication of the need to do a clean installation of Windows on your computer. I would recommend that you backup all data you need to keep (as this procedure will result in all data on your computer being lost), format the hard drive and then reinstall Windows from scratch. This will remove everything from your computer, providing you with a clean slate.