Starting on February 16, Microsoft is going to send out a Windows 7 update
which will change your system in an important way (assuming you use Windows 7): Your system will "phone home" to Microsoft on a routine basis to make sure that you are running a genuine copy of Windows. Are
you running a genuine copy? If you bought your system used, you may not know.
At any rate, there are those of us who don't like the idea of an OS which talks to the internet against our will.
The best bet? Simple: Go to Control Panel, go to Windows Update, go to Change Settings, and then in the field where it says "Please select an option," go for "Never check for updates." If it ain't broke, don't update it.
I'm hoping that we can get through a discussion of this point without hearing from the buy-a-Mac guys and the go-Linux crowd. If I want to deal with proselytizers, I'll invite the JWs inside.