Digging Deeper For Dirt
There are other dirty pockets, too. The power supply has its own cooling fan; it draws some air from inside the case through these slots cut into the front edge of the power supply housing. As you can see, dirt and dust accumulate here, as well.

The power-supply housing's air intakes also show some significant dust build up. (click image for larger view)

And consider this: The power supply fan (visible in Photo 3) was dirty; and the intake for that fan, shown above, also is dirty. Therefore, the inside of the power supply also must be dirty. It's not wise to open up power supplies due to the high-voltage components inside, so we'll have to find a way to clean the inside of the power supply in a later step, despite not being able to open it up.

If the air entering the power supply was a source of dust, what about where air entered the system as a whole? In this system, the intake air holes are on the front of the case (as shown in Photo 2). They appeared clean, but that can be deceptive because those air intakes are not the true metal front of the PC, but rather are part of the mostly decorative plastic "bezel." Looking at the bezel may or may not tell you what you need to know about the true front of the case. So: It's smart to pop the bezel off to see what's going on underneath.

For a thorough cleaning, you have to remove the case's front bezel, usually held on by snaps or screws. (click image for larger view)

In this instance, the bezel has plastic prongs that fit into slots on the front of the PC. To make it easier to remove the bezel, the mounting slots are marked with arrows stamped into the metal of the PC's front. In Photo 14, you can see one such arrow next to my finger. The stamped arrow is pointing to the mounting slot.

Photo 15 (below) zooms in a little tighter and shows you the lower bezel mounting slot, which also is highlighted by a stamped arrow. To release the bezel, you flex each prong just enough to allow it to be pulled out of its slot.

This case design uses stamped arrows to show you the bezel attachment points. (click image for larger view)

Here's the bezel partially pulled away from the front of the PC, which is lying on its right side on a work table. You can more clearly see the bezel's prongs now: Those prongs snap into the slots on the case marked by the stamped arrows we saw in previous photos. The other side of the bezel is held with simple L-hooks; once the prongs are released, the whole bezel swings out and away from the PC with little resistance.

I stopped removing the bezel at about the halfway mark so you can see how it's attached: The PC is lying on its right side, and I'm lifting the front bezel out and away from the metal front of the PC case. Other case designs may use somewhat different bezel mounting details, but most follow the same general pattern. (click image for larger view)

Of course, other designs may differ in the details, but the bezel-mounting concepts are usually generally similar.

Here's why it's a good idea to remove the bezel: Although the bezel's own air-intake holes were clean, look what was accumulating underneath! This is a close-up of the floppy drive opening; other areas under the bezel were similarly dirty.

Just as we suspected, the area beneath the bezel turns out to be a mess. Here, the floppy drive is growing a sweater. (click image for larger view)

Remove any plug-in cards from the system so they and the area beneath them can be cleaned. Make note of any wires you disconnect; a digital camera can be a real help in making a record of your PC's internal setup, so you can recreate it later.

As a final step before we actually start cleaning, we'll remove the system's plug-in cards; a simple screwdriver operation. (click image for larger view)