The consummate image of this purity is the industrial cleanroom, an environment in which terrific pains are taken to eliminate dust, dirt, and contamination.

But it isn't quite like that where the rubber meets the road. Yesterday I was loading some software from my CD-ROM drive onto my hard disk. The installation went flawlessly, and when I was done, I wanted to replace the disk in the drive with another. I pushed the little button, and the light went on, and the drive spun around. Then the light went off again.

I repeated this action about 30 times. Then I pursed my lips the teeniest bit and dialed Compaq. In about eight minutes I was talking to a guy named Mike.

"My CD-ROM drive won't open," I told him.

"Have you pushed the button?" Mike asked. They have to ask.

"Yes. Several times!"

"Well," he said, "you probably have some dust or something in there and that's clogging it up."

"My good man," I told him, rolling back in my swivel chair. "I run a tight ship here, and I assure you, there is no --"

I was stopped by the CRUNCH of my chair caster traversing the microfine surface of my Lotus Smartsuite 97 disk. It had splintered into about eight very sharp plastic shards. Maybe I did need to clean up a bit.

I hung up on Mike and pushed the CD-ROM button a few more times. Assured it wasn't going to work, I unplugged the PC and opened it up. I mean, I only bought the thing a year ago. How much dust could possibly accumulate inside?

I got my answer as I took off the cover, and beheld a blanket of dust bunnies, lying across my components like a flannel coat of fresh gray snow. About half a sweater's worth. Inside the CD-ROM, I did indeed find a little nest of the stuff, clogging the corners.

You see, the thing about computers is that they are electrostatic. The electricity in them causes small particles to gravitate toward them. The monitor does it, your printer does it, the CPU does it, and all the peripherals inside the computer do it.

All the gunk gets into the system and clogs up the venues until the 1s can still squeeze through, because they are skinny, but not those 0s. Then it's time to vacuum, blast, and 409.

You could prevent dust from entering your system by sealing off the vents. But then it would burst into flame.

Cleaning the computer has always been difficult for me. When I am near one, I can think of so many funner things to do with it than wash behind its ears. And some of that fun is the cause of the dirt.

If you are an eater, for instance, the dust attraction is complicated by greasy fingers. A consultant once told me he could always tell which users on a network were developers, from the characteristic blue stains on the metal surfaces -- the grease and salt and oil from the ubiquitous bag of potato chips.

People who smoke may blow the smoke toward the ceiling or away from their equipment, but the equipment still pulls a lot of smoke toward it. For a charming experience, Windex a smoker's monitor (first turn it off) and contemplate what your dustcloth picks up. Not that a nonsmoker's is all that appetizing.

Here's something else to think about: half the "dust" in most people's houses is actually shredded human skin.

But you don't need to eat or smoke or shed. I live and work in the attic of an old house, for instance, and it is just naturally dusty up there.

Be careful with those aerosol gas-blasters. They are suppose to whisk delicate surfaces clean, but can leave a surprisingly potent residue, especially at close range. I once blasted a Colorado backup unit and coated the mirror with a permanent, nonreflective, granite-like substance. Medusa would have been a better brand name than Dust-Off.

So I spent all day today cleaning up the computer room. Vacuuming the bookshelves, sponging the moldings, mounting a fan in the window to blow the bad stuff out toward other people's computer rooms. The PC itself came in for a meticulous cleaning. Before I screwed the case back on, I pinged each expansion card, and was answered with a reassuring chime.

When I was all done, I believed I had created a pretty particle-free system and environment, and I booted up with a feeling of pride in a newfound work ethic. And hey -- the CD-ROM worked.

I made a promise to myself then and there to be cleaner in my work habits. I'm a new man. And I'm going to make it a regular thing, too, and do it all over again next year.