What happens when you restart your computer

Restarting your computer is a common task. Whether it's troubleshooting or installing software and hardware, most computers restart fairly regularly. And those that don't might start showing issues until they're restarted. What happens when you restart your computer? It's actually a pretty simple process involving some pretty basic commands.

What happens when you reboot?

Most of your computer's shutdown and restart processes are controlled by ACPI (advanced configuration and power interface) power states. Power states come in several flavors and are controlled by the motherboard. These power states come from ACPI, or Advanced Configuration and Power Interface, which controls power management in your PC. There are a few important power states that help us understand how the computer works.

• G0:powered on and running; the operating state of your computer
• G1:Sleep
  • S1:RAM and CPU stay on, but CPU does not process instructions. Devices are powered off.
  • S2:CPU is off, but RAM power is maintained, preserving memory contents
  • S3:Everything except RAM and peripherals that can wake up the computer, such as the keyboard, are off. This is your computer's "sleep" state, which is triggered from the Windows Start menu.
  • S4:The contents of RAM are written to disk and everything shuts down. This is "hibernate" mode. The only difference between this and G2 is the resume process:you won't need to boot your PC to come back from this power state.
• G2:"Gently." This is the typical shutdown state of the computer. Power is off to everything except devices that are listening for power up.
• G3:mechanically off, cannot be started until reset to G2.

Why does restarting solve so many problems?

Restarting is a key troubleshooting step as it resolves a wide variety of issues. But how?

During the reboot process, all computer logic is reset. This means that the CPU, memory, controllers, and peripherals all receive their reset commands and return to their boot states. By erasing everything that happened before, this reset can often fix problems by resetting things to their "new" state. Of course, this does not mean that the problem will not reoccur. But this fresh start often removes the offending gremlin, at least temporarily.