Does that PC sitting next to you sound like a Learjet revving its engines for takeoff? Okay, it's probably not that bad, but many PCs are loud enough to be distracting or just plain annoying, especially if your workspace is otherwise tranquil.

To their credit, PC makers are beginning to consider acoustics when they design systems. But too many PCs are still built with inexpensive cooling components that can create a noisy system.

The main sources of noise are motors and spinning components such as the hard drive, CPU fan, case cooling fans, and power supply fan. The power supply fan and CPU cooling fan are usually the biggest culprits. Fans and hard drives also produce vibrational noise that's magnified by the PC case or the surface it's sitting on (see step 1 ).

As processors, hard drives, and graphics boards get faster, they produce more heat, so more cooling is necessary, and cooling tends to beget noise. But there are ways to reduce the cacophony while achieving adequate cooling. On the next page: the parts for a quiet PC. On the third and fourth pages: steps that start with the simple and move up in complexity and expense.