I bought and set up a PC for a friend last February, insisted she kept Norton Antivirus up to date, etc, etc. It worked fine for a few months and then literally seized up. I knew it had something on it, but it was eating up the connection so I couldn't update the Norton or download something else to kill it, and it wouldn't allow reading of .EXE files off CDs so I couldn't load something up to kill it - stalemate, and my friend looking at me with labrador eyes, swearing she hadn't downloaded anything stupid. I had to wipe the hard drive and start again.
My point is that the nasty crap floating around out there in the ether has moved on enormously in the last year or so and is far more dangerous now, and the likes of me who used to have a good idea of what to do to prevent any problems are well out of date in a short period of time. Antivirus is no good now on its own - no matter how well it works, the nasties come in the back door, no need to download anything or press the wrong button. XP is full of holes and all you have to do is to be online, a firewall is the only thing that helps in this regard. One of the buddies who works in IT said he has fixed up dozens of PCs for people in the last 9 months that were just as crippled, as soon as he wiped the hard drive and reloaded everything with antivirus, SP2 and a proper firewall, within 30 minutes of going online there had been multiple unauthorised attacks through the backdoor that the firewall dealt with. I realise this is baby stuff to most of the people on this forum, but the average Joe has been hard hit for the past while, so much so that here in Ireland the government have launched an information campaign, distributed leaflets and started a website -
www.makeITsecure.ie. All good sensible stuff, and given carpetbombing Microsoft isn't an option, other countries should do the same.