For Mac users must already know that Apple machine and OS X are often mentioned very stable also has a lot of obstacles. Have a Mac you can not sleep or bluetooth does not work, WiFi is often dead and other small events that make resentful? Do not panic, because the hardware is not necessarily broken, before bringing the Mac you to first try resetting PRAM service or NVRAM.

What is the PRAM or NVRAM?

PRAM (Parameter Random Access Memory), NVRAM (Nonvolatile RAM) is a place of memory that stores specific information such as the speaker volume, screen resolution, start-up disk, and others.

When to reset the PRAM or NVRAM?

When the Mac you have problems that should not have happened. For example, the sound suddenly disappeared, bluetooth mouse movement is wrong, trackpad suddenly not functioning properly, the resolution of the screen suddenly changed. Anyway events suddenly wrong and improper.
How to Resetting PRAM and NVRAM
PRAM and NVRAM reset

How to Resetting PRAM and NVRAM 

1. Turn off the computer, wait a few moments.
2. Turn on the computer
3. Press and hold down Command + Option + P + R, resistant to the gray screen appears
4. Remain resistant to the Mac boot for the second time.
5. Release the button.

Now PRAM and NVRAM is reset, it could be hours in OS X would be wrong. Signs of success reset PRAM and VRAM in point # 4, the Mac will boot back up.

For those who use the iMac, reset the PRAM and VRAM can still be done using the Apple Wireless Keyboard, no need to look for a wired keyboard.
Do not panic and rush to the service if the computer is no problem. Try resetting the PRAM and NVRAM first.