This one’s pretty big–nine million Windows users affected, maybe more. It can spread via networks or USB flash memory sticks or MP3 players, and cracks your security by trying massive numbers of possible passwords on your computer. While there are reports that the worm is not very harmful or hasn’t caused much damage yet, things might be a bit more scary:

Once a machine is infected, the worm can download and install additional malware from attacker-controlled Web sites, according to the company. Since that could mean anything from a password stealer to remote control software, a Conflicker-infected PC is essentially under the complete control of the attackers.

The nine million number is also sobering when you realize that this threat has been around for a month, and Microsoft has even issued a patch for it. Sadly, Microsoft security has too many holes, many of them in the introduction of anti-virus programs. Many people think that the free 3-month trial anti-virus software they get with their computers is not a trial, and never buy it, leaving their computers unprotected. Others get Vista and get so annoyed by the constant security messages that they turn it off, but don’t replace it with something else.

Not that having anti-virus software is such a great alternative–you have to deal with the cost of buying the software, the drain on system resources, making sure that it is kept up-to-date, and dealing with the constant messages telling you of infections or attempted infections.

It’s enough to drive you to buy a Mac.