How can a computer set its time correctly after turning on with out giving it any power supply for many days?

Question

How can a computer set its time correctly after turning on with out giving it any power supply for many days?

Answer 1

Computers have a small battery on the motherboard that keeps the clock running.

Answer 2

The computer motherboard has a small round button-battery attached to it, which lasts for several years. This keeps the computer's internal clock running even when the power is off and unplugged.

Answer 3

All computers have a small rechargable battery on the motherboard that keeps the clock running.  When you turn your computer on it recharge the battery  and when computer is off the clock is still stay on

Answer 4

two reasons there a little battery on your computer which powers up the bios it keeps the time date it's a little clock if you like the battery is recharged while your on the computer. The second Xp and vista have the clock set up so it will goto time.windows.com when you connect to the internet which will keep the corect time. You can change this to turn off as I do by right clicking your clock hit adjust time\date and you change the internet time to do not connect.