[SOLVED] I built my first computer, booted once but then didnt

[BluZebra]

So i just built my first computer, and before putting it into the case i put it on my motherboard box and test booted. i successfully booted into the bios. then i put it in my case and i pressed the power button...and nothing. no mobo leds or anything. i tried to reseat the psu cables, both the ones on my modular psu and the ones attached to the motherboard and the graphics card, and i also tried to remove the power button connectors and tried to jump the cable on my own. the only thing i saw flashing on my mother board was the FLASH BIOS button on my tomahawk max when i pressed it. also i did the paper clip test on my psu and confirmed it was working, but the fan doesnt spin when i connect it to the motherboard. i disassembled my computer again and am now back on the motherboard box. still no luck. please help because i have no idea what to do

 

[white.a.drew]

So i just built my first computer, and before putting it into the case i put it on my motherboard box and test booted. i successfully booted into the bios. then i put it in my case and i pressed the power button...and nothing. no mobo leds or anything. i tried to reseat the psu cables, both the ones on my modular psu and the ones attached to the motherboard and the graphics card, and i also tried to remove the power button connectors and tried to jump the cable on my own. the only thing i saw flashing on my mother board was the FLASH BIOS button on my tomahawk max when i pressed it. also i did the paper clip test on my psu and confirmed it was working, but the fan doesnt spin when i connect it to the motherboard. i disassembled my computer again and am now back on the motherboard box. still no luck. please help because i have no idea what to do

Pull the lithium battery from the mobo with no power connected and wait 10min

 

[kurdtnz]

Full system specs?

 

[BluZebra]

Full system specs?

ryzen 5 3600
b450 tomahawk max
wd sn550 1tb
gtx 1660 super
msi a650gf
2*8 trident z rgb

 

[BluZebra]

Pull the lithium battery from the mobo with no power connected and wait 10min

so i did do this but still nothing has happened. what now?

 

[kurdtnz]

What speed is your RAM? Also, Do you have the RAM seated in slots A2 and B2,(2nd and 3rd slots?) If it is not booting still, try using just one RAM stick and see if it will boot.

 

[BluZebra]

What speed is your RAM? Also, Do you have the RAM seated in slots A2 and B2,(2nd and 3rd slots?) If it is not booting still, try using just one RAM stick and see if it will boot.

Its 3200 mhz. Ram sticks are seated in A2 and B2 (2nd and 4th slots) I'll try booting with 1 stick. Like i said in my post, my system did boot once, and all 16 gigs were showing in the bios

 

[kurdtnz]

Its 3200 mhz. Ram sticks are seated in A2 and B2 (2nd and 4th slots) I'll try booting with 1 stick. Like i said in my post, my system did boot once, and all 16 gigs were showing in the bios

sorry, I meant 2nd and 4th,my bad. Ok, also, was the RAM on your motherboards QVL (compatibility) list?

 

[BluZebra]

yep, its on the qvl list. i tried with one stick, but still no luck. At this point , im wondering if there is just an issue with the way i jump the pins

 

[ChumP]

You need to short(touch both of them with a piece of metal) the Power switch pins on this diagram if you're still not sure:

Are you sure that everything is plugged in properly? Check everything on this guide before you go any further:

"No POST", "system won't boot", and "no video output" troubleshooting checklist

"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...

forums.tomshardware.com

As a last resort thing, You should pull the motherboard out again and check if everything works. If it works fine outside the case, check if the motherboard is touching the case anywhere... check thoroughly.

 

[BluZebra]

You need to short(touch both of them with a piece of metal) the Power switch pins on this diagram if you're still not sure:

Are you sure that everything is plugged in properly? Check everything on this guide before you go any further:

"No POST", "system won't boot", and "no video output" troubleshooting checklist

"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...

forums.tomshardware.com

As a last resort thing, You should pull the motor out again and check if everything works. If it works fine outside the case, check if the motherboard is touching the case anywhere... check thoroughly.

Issue is fixed now. Thanks for all the suggestions. turns out what i had to do was change the connector on the cpu cable on the psu. not too sure what happened. currently installing windows