HOW to do a PC HARD POWER  RESET           
Is your PC dead?
BIOS screens dead too? Monitor shows NO SIGNAL or the like?
This page is a full cure, or only a band aid, if any PC locks up in sleep (or hibernate) mode and drivers are bad it will repeat lockup.
If the lockup was from ESD or Lightening surges this is solid cure. (until ESD hits again)

I will do this page in 2 parts, one is for PC is dead (how to do simple hard power reset, and how to do service on  a PC, and not blow parts to H3LL.
The PC called a Laptop remove the big battery and test with no big battery there on AC power Pack only. (if a battery shorts the PC will be dead)
If the PC is Deaktop there is no huge battery there, but all PCs have  RTC coin cell battery that if dead , BIOS screens can go dead, and the PC.

If the RTC coin cell battery is dead, replace it below 2.9vdc. (it costs only $1 to replace it, and only lasts for 5 to 7 years)  On any desktop this is childs play on Laptops , from easy to pure hell is possible on laptops.(RTM?)

This is  just the steps for for a hard reset, not doing service on the PC, covered last.
This is not hard at all, and resets all ESD and latchup events, even stuck in sleep mode events. (the latter is bad software drivers in the PC's OS)
If a laptop that  huge battery in the PC must come out first, some are easy , just drop off bottom and some thin notebooks pure hell to reach. (on a real desktop this is just 4 steps, and is really childs play simple)

  1. Remove the Thick A.C. Line cord (cable) from the wall Outlet
  2. Push the front power button for for 1second  up to 3 times,  if the fans stop twitching that tells you all CAPACITORS in the PC are now fully discharged (goal #1)
  3. Wait 5 minutes, touch nothing. 
  4. Put back the A.C line power cord in the PC and now the PC runs ok or at least BIOS works and its keys all work.
Just 4 steps, to reset it,  is this simple enough?
If this fails make step 3 , 1 full hour long. (even over night in very extreme cases)

Servicing any PC and not wanting to blow up expensive modules inside any PC.? (work safe don't blow up $300 components, ok?)
Rule #1 on all PC's is never remove or swap parts inside hot,  that means with the AC line cord to the wall AC jack, at anytime, if you do this wrong that is called illegal HOT SWAPs or hot plugged.!
Do step 1 to 3 above then... (on a laptop of any kind the big battery was remove long ago above)

  1. Let the PC site dead per above,  for say 1 full hour and hope for all capacitors inside, are fully discharged. (goal #1 doing any service inside) OK?
  2. At this point you can work on the PC inside and not damage parts removed or installed hot swapping them.
  3. The PC is now safe to work inside, now.
  4. Never hot swap any DC power cables  inside any PC, with AC line cord connected, the PSU never really turns off is why this is true.
  5. Do not hot swap PCI cards of any kind nor SATA power or GPU card power cables. (most have colored wires, and are DC power)  See link above for other rules on power.

The hard reset cures these causes of  failure. (some are only temporary , and stated last in the list.)
  • ESD events, you the human are charged up with electrons,  just like getting a spark from a door knob touched ESD cause CMOS chip latchup (passive or active) ( the coldest days of winter are worse at 0% humidity)
  • Lightening events,  (or far worse there is no limit to worse)
  • Power line surges of any kind for any reasons.
  • Sleep mode stuck (only new and matched drivers is the cure)

Parting shot, I have seen some folks try to change the BIOS from Legacy mode to UEFI mode (or the reverse) and now wonders why BIOS is dead and the HDD dead too, this is by clear intent and design.
UEFI mode, marries the HDD to the OS and BIOS and the dang Video card, if you change things that attempt to unmarry the HDD, the BIOS (UEFI) will go dead.
This prevents moving any UEFI HDD to a second PC, and stealing your data. (by DESIGN)
Dead PCs have many more causes more than just the above one cause (latchup) lots more there are. AS SEEN HERE.
This page above is no panacea,  it is only one very common reason for any PC to latchup and go dead. (one of say 20 reasons, possible)

If you don't like UEFI why are you using it?,  the cure is simple its legacy mode, go to forum and ask how to go from UEFI boots to Legacy Boots, (answer reInstall the OS fresh)

version 3.  12-9-2017 (revised 1 -1-2020)   I split the page so folks don't get confused. (latch up and service mode)