Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Possible Duplicate:
How does a computer restart itself?

  1. if we want to on our PC we press on switch then computer is start..
  2. if we want to shutdown our PC we give commond for switchoff .
  3. But there is an interesting state between Shutdown and Statup ."Restart..!".

?. what happened internally and How a PC is going shutdown and without press on button it automatically rebooted itself?

share|improve this question

marked as duplicate by Sathya Nov 15 '11 at 8:08

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 1 down vote accepted

ATX power supplies are under the control of the motherboard, not of the switch. Normally the power supply provides only a small standby current; the power switch on such a machine, actually a momentary NO switch, signals the motherboard that it should put the power supply into full operation. An ACPI command is used to tell the motherboard to put the power supply back in standby, shutting the machine down.

But a "restart" is actually just the CPU being sent to a specific location in BIOS and running the boot routines fresh from the beginning.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.