How Secure is your Computer? is the question posed by this article. If you are running Window XP SP1, the answer is: not very. If you are running Windows and you are connected to the net, you have to update it constantly. End of story. Same goes for any operating system; but more so for Windows just due to the fact that most of the exploits are designed to be virulent so they attract popular OS's as a matter of course. The article states:
SP 1 was attacked 4,857 times. It was infested within 18 minutes by the Blaster and Sasser worms. Within an hour it became a "bot," or a machine controlled by a remote computer, and began attacking other Windows computers.Another article of note along these lines is Windows XP: Surviving the First Day where the Incidents.org crowd explain how you can install XP and get it patched up *before* getting hacked.