File this one in the strange-but-true category. The next time your computer goes on the fritz, you might want to call a lighting specialist before lugging it back to the computer store. Your PC problem could be related to your fluorescent lights.

Back in 1991, the U.S. Environmental Protection Agency launched the Green Lights Program to save energy and reduce pollution. The program has an impressive list of more than 1,000 partners, including corporations, universities, hospitals, and schools. Green Lights partners install new energy-efficient electronic ballasts in their lighting fixtures. (A ballast is a small component in fluorescent lights that transforms and regulates the incoming voltage for the lamp.)

It sounds great. The only problem: some retrofitters and power-quality consultants say the new ballasts can sometimes cause harmonic distortion. That's bad. In our power systems, voltage is an alternating wave that travels at certain frequencies. The new ballasts increase the frequencies, which in turn distorts the shape of the wave. And excessive distortion can cause computers to lock up or even reboot. Apparently, we've known about harmonic distortion since Edison fired up his first bulb, but only recently has a flap erupted over whether newfangled ballasts can cause it. Some experts remain skeptical: "It's certainly theoretically possible," says Steven Leeb, Carl Richards Soderberg Assistant Professor of Electrical Engineering at MIT. "It's just that I personally have never seen it."

But John Belcher, executive president of United Energy Associates Inc., a lighting-management consultant based in Winter Park, Fla., says he's witnessed the phenomenon on many occasions. He suggests that people looking to retrofit should address the potential problems with their retrofitter. "People talk only about the upside," says Belcher. "But there can be a downside if the system isn't properly designed."

-- Joshua Macht