A lot has happened over the past six years, Microsoft is as big as ever, they've been taken to court in the US and the EU but still keep up their anti-competitive practices. A lot of viruses have come to infect the computing world mainly due to a combination of bug-ridden Microsoft software and people not upgrading said buggy software.
Microsoft are running scared of Free Software (also known as Open Source) such as Linux and Apache which are threatening their market share in the server area, with great free products such as Mozilla and OpenOffice.org there's viable alternatives to their products on their desktop.
Why am I antiMicrosoft? Well it's because of the attitude of the company, they've shown in the past that they can't stand competition and will do everything within their power to crush their rivals whether the means is strictly legal or not. Having no competition limits innovation, the US legal system, once George Bush got into power, decided to just give MS a slap on the wrist despite them being found guilty in an anti-trust trial. Fortunately, things may be slowly changing thanks to the increasing popularity of Linux and other Free Software - basically the only way to compete with Microsoft is to change the rules, building products and services around a free base rather than making money off software licences. This approach has Microsoft worried as they traditionally make money out of selling software rather than services around the software. But it is still an uphill battle as Microsoft still has the dominant position.
If you still use Windows then there's a few things you should always do to protect yourself from Windows viruses and stop others suffering from their effects: