Sometimes PC won't boot

[Cupra]

Hello,
I've built my PC a few months ago.
Some specs:
Motherboard: Asus PRIME X570-P AM4
CPU: AMD Ryzen 7 3700X
GPU: ASUS ROG RTX 2070 SUPER STRIX
PSU: Corsair 750W 80+ Gold RM750i
RAM: Corsair Vengeance RGB PRO 2x8GB DDR4 3200MHz CL16 Kit
M.2: Samsung 970 EVO M.2

Since the beginning i've noticed that every once in a couple of startups the system will turn on all of the LEDs in the case (and the graphics card), the fans will ramp up like a normal boot.
In the end there is no display output and my keyboard and mouse won't light up (or any other USB device connected).
My mobo does require 8+4 pin to the CPU socket but I have only the 8 pin connected because my PSU doesn't come with an additional empty 4 pin slot - Is there a chance this might be the problem?

 

Most of the times it happens after the PC hasn't been turned on for about a day.
It happens about 3-4 times a week, when it happens i press the reset button on my case and the computer boots perfectly every time after that. (this is the reason I don't think its a mobo/psu problem - everything lights up even if the pc won't boot including the GPU)
Other then that the PC is brand new and works perfectly fine.

I've tried disabling "Windows Fast Boot" - the problem still occurs.
I went through the bios menus and saw "Fast Boot" enabled, is there any chance ASUS's fast boot is the problem?

I really need your guys help,

Thanks!

[Bombastinator]

Howdy and welcome

 

Ah the “this computer works but only barely”problem.  Seen this one before.  Several possible issues.  I’ll generally list the ones I remember off hand.  I can’t offer any solutions and I’m probably missing a few.  These are in the order I am thinking of them in NOT most likely:

 

1) windows configuration issue:  the HD is misconfigured and Windows can’t always find it. If this is the case it will post fine but windows will have to go through a process to find the drive.  Often takes a long time and sometimes fails.  It will find the drive eventually but other stuff may time out in the meantime.

 

2) cmos battery issue.  Defective battery that doesn’t hold power combined with super power saving PSU that doesn’t use enough power to keep the cmos up.  If you leave the machine off too long cmos gets wiped and has to rebuild.  Battery still has a little capacity though so a Reset would mean the machine starts up again with a still working battery.

3) Bios settings issue.  There is a setup issue on bios where boot and reset are different and the boot setting doesn’t work but the reset one does.

 

There will be more.  Probably better ones.  This is just what my old crusty brain is remembering atm.

 

 

Edited August 27, 2020 by Bombastinator

[Cupra]

35 minutes ago, Bombastinator said:

Howdy and welcome

 

Ah the “this computer works but only barely”problem.  Seen this one before.  Several possible issues.  I’ll generally list the ones I remember off hand.  I can’t offer any solutions and I’m probably missing a few.  These are in the order I am thinking of them in NOT most likely:

 

1) windows configuration issue:  the HD is misconfigured and Windows can’t always find it. If this is the case it will post fine but windows will have to go through a process to find the drive.  Often takes a long time and sometimes fails.  It will find the drive eventually but other stuff may time out in the meantime.

 

2) cmos battery issue.  Defective battery that doesn’t hold power combined with super power saving PSU that doesn’t use enough power to keep the cmos up.  If you leave the machine off too long cmos gets wiped and has to rebuild.  Battery still has a little capacity though so a Reset would mean the machine starts up again with a still working battery.

3) Bios settings issue.  There is a setup issue on bios where boot and reset are different and the boot setting doesn’t work but the reset one does.

 

There will be more.  Probably better ones.  This is just what my old crusty brain is remembering atm.

 

 

1) My selected boot option is windows boot manager and my partition is UEFI so i doubt that's the problem?

2) Do you think I should replace the CMOS battery? is it possible that it's defective even though most of the times the PC boots completely fine?

 

When it happens everything inside the case lights up but I don't even see the ASUS's logo and I cannot access the bios settings, it's just a black screen.

 

Thank you for your reply!