"Kent Brockman: Professor, without knowing precisely what the danger is, would you say its time for our viewers to crack each others heads open and feast on the goo inside?
Professor: Yes I would, Kent."
Not really such a simple plan, as it happens, not least because it doesn't leave you intrinsically safer than when you started. These are all important things to do, but: Applying the security patches to Outlook still leaves you using Outlook, which is frankly just plain something that no one should do without a paycheck riding on it; applying the Windows security patches is important, but it leaves your ports open to attack from the outside world; and checking for spyware is something you wouldn't have to do if you didn't run Outlook or IE in the first place.
Here are my three steps, roughly in order of importance:
These three steps will make your computing life markedly safer.
Notice the absence of an admonition to update Windows, install a spyware scanner, or install a virus checker. Those are great steps, they're important, with importance roughly in the order in which I've given them, but these three measures I highlight are by far the most important and powerful things you can do to enhance the security of your own system. Do them, and it becomes very difficult for a worm, trojan, or virus to infect even an unpatched, un-virus-scanned system.