A computer is a very unique machine. It has many different parts and a lot of different noises. Some parts are hot, and some are cold.
Computers have many different sounds that they make. Depending on the sound it makes, it could have a problem. When your computer beeps at you. It normally means that an error has occurred and that it needs to be fixed. Or it is a game and it is supposed to make sounds like that. But there is one sound the computer always makes. That sound is a little hum that everyone notices. That hum is the fan in the back of the computer running. That fan cools down the CPU. (Central Processing Unit)
Inside your computer you have a CPU. The CPU can be hold, warm or cold. If you leave your computer on all night, the CPU will be hot. This is because electricity runs through the CPU and makes it hot. If it was turned off during the night, and you touched it in the morning. The CPU will be cold. This is because the CPU was off and there was not electricity to keep the CPU warm. If your CPU becomes to hot, a fan will be turned on to help cool the CPU down.
Depending on the model of your computer, your CPU might have a different look to it. Older CPU s (Such as a 486, or Pentium I) are square and flat with a bunch of metal prongs on the bottom of it. The top of the CPU is metallic. Some are silver, and some are gold. It depends on the manufacturer.
That humming noise your hear right now, that s just your fan cooling down your CPU. Oh, and don t touch the CPU, it might be kinda hot.