Does your PC literally start emitting a “roar” every time you boot it up? Old PCs often tend to be a bit noisy. The first thing that you have to realize is that the main cause of CPU noise is heat. The more your processor or motherboard gets heated, the faster the CPU fans will spin, thereby cranking up the decibels emitted by them. Hard drives can also emit quite a lot of noise when these get old, and the reading head get slower, the drive will emit some noise when working. If you find this cacophony disturbing your concentration on a regular basis, try the following steps:

1. Defragment your hard drive: After you defragment your hard drive, you will often notice a considerable decrease in the noise level of your PC. This is because the reading head of your hard disk won’t have to travel around much over the platters in order to look for data that you are trying to access. This will reduce the noise coming from your hard drive to quite an extent.
2. Wrap hard drive in rubber bands: Some PC users claim that they have been successful in reducing hard drive noise by wrapping the drive in a series of rubber bands. The bands dampen the effects of the vibration that the drive goes through, especially when running CPU-hungry tasks. However, the rate of success varies to quite some extent between users.
3. Go for a new hard drive: Most hard drives of present day are equipped with sound dampening technologies of some type. These drives have fluid dynamic bearings, which allow the platters to remain almost silent, even when spinning at a very high rate.

These solutions can help you cut down on hard drive noise considerably. Another principal source of the CPU noise is the CPU fans. These are difficult to silence, however. In order to cut down on the noise of the CPU fans, you will often have to replace the fans. There are various models of CPU fans available now, which run almost silently. Also, try to keep your CPU fans clean from dust and dirt at all times. Open your CPU case at least once in two weeks, and clean the fins of the fans with a small handheld vacuum cleaner, or a soft brush. The cleaner the fans are, the quieter those will run, bringing down the sound level of your entire CPU.