Question Computer will not boot unless USB connected

[IrishXP]

Hey there, I'm new to Tom's Hardware so my apologies in advance if I am asking in the wrong place.

My old rig is having a very strange power cycle issue that requires me to plug in a USB while it is booting in order for it to start.
This problem started out as me having to hold the power button for a few seconds before the system would boot up and over the past 2 months or so of trying to troubleshoot I found that
when I power my system down it will 1 press start right back up, however if I leave it unpowered overnight the next morning it will require a USB plug in while pressing the power button in order to start up.
The usb I use doesn't matter, the usb slot also doesn't matter. I can use the xbox 360 controller, a phone charger, or a flash drive to get the computer to boot up right away.

When I push the power button all of my USB devices immediately light up and pulse as they are getting a pulse of power (soundbar, xbox controller, phone charger).
None of my computer fans or lights start up at this phase.

A few things that I have tried already -
Powering on the system with no USB's connected at all
Powering on the system from the Motherboard onboard power button
Replacing the CMOS battery
Powering on the system with no cables connected except for PSU.

the specs for this system are :
I7 3770k Ivy bridge Not overclocked
980gtx not overclocked
16gb ram
750watt power supply
Zalman z5 cool innovations case


This system was built in 2009, so she's getting really old and I understand a new PSU could be in order but I would like to eliminate all possibilities before I start replacing components.
Thank you in advance for taking the time to read my question. I look forward to a resolution!

 

[Colif]

If PSU is as old as rest of system, I would try a new one.

 

[IrishXP]

If PSU is as old as rest of system, I would try a new one.

Thanks for your response Colif! I am currently on this system, it has no other signs of a PSU flaw. I can game on it perfectly fine with no hangs, crashes, or random restarts. I would like to eliminate possible issues before I start throwing $ in hardware at the problem. Thanks!

 

[Colif]

I was just going from your clues.

when I power my system down it will 1 press start right back up, however if I leave it unpowered overnight the next morning it will require a USB plug in while pressing the power button in order to start up.

unpowered as in off? that isn't a windows problem

You can test other parts to be sure but as only time you have problems is start up, its unlikely to be some things.

Memory - Try running memtest86 on each of your ram sticks, one stick at a time, up to 4 passes. Only error count you want is 0, any higher could be cause of the BSOD. Remove/replace ram sticks with errors.
Memtest is created as a bootable USB so that you don’t need windows to run it

CPU - https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool

tried running without GPU attached? see if it makes any difference at startup

I doubt its caused by storage, but what ssd/hdd do you have?

 

[IrishXP]

I was just going from your clues.

unpowered as in off? that isn't a windows problem

You can test other parts to be sure but as only time you have problems is start up, its unlikely to be some things.

Memory - Try running memte2st86 on each of your ram sticks, one stick at a time, up to 4 passes. Only error count you want is 0, any higher could be cause of the BSOD. Remove/replace ram sticks with errors.
Memtest is created as a bootable USB so that you don’t need windows to run it

CPU - https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool

tried running without GPU attached? see if it makes any difference at startup

I doubt its caused by storage, but what ssd/hdd do you have?

Unpowered as in powered down the night before going to bed.
I haven't tested the memory, however I did replace it about 2 years ago. This problem has been present for about 2-3 months now.
I haven't had any BSOD, crashes, or long hang ups.
I haven't tried booting it without the GPU

Motherboard is Asrock extreme4
Storage is samsung evo 8 500gb SSD, The OS is loaded on this
Secondary storage is a WD 7200rpm 1tb hdd.

I'm wondering if it's something bios related as it's only present during startup, the USB ports are not failing at all during normal use. What I find incredibly strange is that I can shut down the system and have no problems starting it back up, it's only after it has sat for a few hours that the problem replicates.