Holding down the power button on a PC while disconnected from power

Many times I would call tech support, and they would say turn off the laptop (take out the battery, hold down the power button, and try turning it back on. I have always wondered what purpose this serves. I recently read a article specifying for mac computers that this resets the SMC. Does doing this with a windows PC have the same effect? Is there a SMC inside all computers? What effect does this action have on non mac pcs? Is it the same for desktops?

repair

rubixibuc

Posted 2012-02-16T09:34:15.310

Reputation: 1 492

Answers

It drains all residual power from the motherboard and memory modules, what that actually resets depends on the design of the motherboard.

As Gateway explains it:

The process drains stored electrical energy in some critical circuits on the motherboard. These circuits start the computer properly.

Moab

Posted 2012-02-16T09:34:15.310

Reputation: 54 203

I'm not sure if its universal but its also true of thinkpads, and some other systems (according to the comments and this post about HPs ) and apparently even tablets.

Reasons range from ACPI resets, to static removal, to MAGIC. Its worth trying out, but dosen't always work in my experience

Journeyman Geek

Posted 2012-02-16T09:34:15.310

Reputation: 119 122

also on some android tablet type items it slamms them off when hung. On Desktop PCs depending on how the Setting in windows and bios , the Off switch performs 2 functions, Quick press , is proper shut-down, Longer than 4 second press is SLAM the PSU into off state. really bad thing to do when running. Then when having Bios issues usually when overclocking, Slamming the power off , can drop the bios back into "being able to post" by temporarily setting default/standard bios settings. It doesnt reset the saved bios. It also depends on the Bios/motherboard – Psycogeek – 2012-02-16T09:47:04.330

This may seem like a silly question, but doesn't static destroy ICs, can it actually just render them temporarily useless? – rubixibuc – 2012-02-16T09:47:55.967

1Honestly? The static explaination sounds almost as bad as the MAGIC explainations. ACPI resets are the least j00j00 explaination i have heard. – Journeyman Geek – 2012-02-16T09:53:13.277