PC Wont turn on

[IbanezMike]

Hey guys, I built up a PC for my brothers girlfriend a few months ago and it had been working fine. One day she was just going through an email and the PC just turned itself off, no power outage, no sparks or sounds, just turned off and wouldn't turn back on since.The entire PC and everything is completely brand new. 

Things I have tried:

• I have checked all cables and connections
• I have taken the header for the PC switch off and shorted it and the PC and back fan spin up for around 3 seconds before stopping again. This happens pretty much each time I try to short the power switch.

The PSU Does have an on and off switch, and yes it is in the on position. The case has an RGB strip which lights up as soon as the PC receives power and is turned on, so there is defiantly power going to the PC.

Other then that the PC won't fully turn on or boot at all. . If anyone has any options I would love to hear them!

PC Specs:

ASUS GeForce RTX 3060 Phoenix LHR 12GB

Intel Core i3 12100 Processor

ASRock B660 Pro RS D4 Motherboard

Corsair Vengeance LPX 16GB (2x8GB) 2400MHz CL16 DDR4

SilverStone SFX-L Platinum Modular 700W Power Supply

Kingston NV1 M.2 NVMe SSD 1TB

[BiotechBen]

Short the CMOS pins. Occasionally PCs just need a BIOS reset when they crap themselves.

[Bombastinator]

52 minutes ago, IbanezMike said:

Hey guys, I built up a PC for my brothers girlfriend a few months ago and it had been working fine. One day she was just going through an email and the PC just turned itself off, no power outage, no sparks or sounds, just turned off and wouldn't turn back on since.The entire PC and everything is completely brand new. 

Things I have tried:

• I have checked all cables and connections
• I have taken the header for the PC switch off and shorted it and the PC and back fan spin up for around 3 seconds before stopping again. This happens pretty much each time I try to short the power switch.

The PSU Does have an on and off switch, and yes it is in the on position. The case has an RGB strip which lights up as soon as the PC receives power and is turned on, so there is defiantly power going to the PC.

Other then that the PC won't fully turn on or boot at all. . If anyone has any options I would love to hear them!

PC Specs:

ASUS GeForce RTX 3060 Phoenix LHR 12GB

Intel Core i3 12100 Processor

ASRock B660 Pro RS D4 Motherboard

Corsair Vengeance LPX 16GB (2x8GB) 2400MHz CL16 DDR4

SilverStone SFX-L Platinum Modular 700W Power Supply

Kingston NV1 M.2 NVMe SSD 1TB

Should have two external switches the rocker switch on the power supply and a soft momentary switch with no off or on on the front or top of the case.  Perhaps time to pull off the side panel and see if there are lights or movement when the thing is powered. This could be no power to the PSU, no power from the PSU, or no post at this point.