Here's a spooky scenario: It's Feb. 18 and you've just plopped down onto the couch after a tough day at work. You grab the remote and click on the television, yearning to slip away into "American Idol." Only instead of casting your tired eyes upon the bubbly visage of Ryan Seacrest, you find yourself gazing at ... a screen full of fuzz and snow.

An alien takeover? Not quite. It's just an avoidable consequence of television's great digital transition.

At midnight on Feb. 17, 2009, the TV stations will stop broadcasting analog signals and switch completely to digital. That will have absolutely no effect on most households, which already watch digital programming.

But the estimated 9 million Americans who still rely on those old metallic rabbit ears or rooftop antennae will have to make some changes or risk losing access to their favorite shows.

In the run-up to the conversion, television executives are going all out to get the word out.

"Our mantra is 'Leave no viewer behind,"' says Scott Walton, executive director of communication for Bay Area station KQED-TV. "In a way, it's like that period right before Y2K, when a big question mark hung in the air. We can only hope that, like Y2K, things end up pretty clean."

Speaking of big questions, we realize you might have some of your own, especially if you're shopping for a TV this holiday season. Fortunately, we've got some answers:

Question: Are they doing this to annoy us?

Answer: It just seems that way. Federal law has mandated the switch to digital broadcasting. Not only will it offer more programming options, it will free up the old analog airwaves for public-safety needs such as police, fire and ambulance services, as well as advanced wireless services for consumers.

Most important for viewers, digital technology will provide a sharper picture, brighter colors and superior sound.

Unfortunately, it will do nothing to make Howie Mandel less irritating.

Question: Do I have to do anything?

Answer: Not if you have a digital TV or a television hooked up to cable or satellite service. You are already ahead of the curve and are free to continue vegging out on the couch.

But if you're still using rabbit ears or a rooftop antenna, you have the following options: (1) buy a digital-to-analog converter box and connect it to your analog TV; (2) buy a digital TV (a TV with a built-in digital tuner); (3) subscribe to a cable or satellite pay service; (4) ditch television altogether and take up reading.