Pc not posting with gpu in

[RDgamer64]

Hi so i’ve been having a problem with my pc, i am personally buying and selling pc’s and on my selling pc i had to update the software on the gpu (the r9 380) 

but when the update was near finish the wholle system shut down and the gpu started ramping up the fans i was like oke it’s done ig with the update but i din’t execute anything

 

so then after a few minutes of the gpu fans ramped up and there was no post after the system restart or what ever that was.

 

i din’t have time to go futher so i get back the other day, and i turn on the system and no post, i was like that’s wierd try again after a whille  stil no post, i trouble shoot everything needed nothing worked, the i did the last thing that came to mind and i unplugged the gpu power plugs and boot it up.

and gues what it boots up without the gpu plugged to power (but in the pci slot)

 

so i don’t k ow what the hell is going so came here for some help. I want the gpu to work again but i just am confused af as in why it doesnt work

 

specs-

i3 6100

8 gb 2133 corsair vengance lpx

r9 380

 

[Biohazard777]

26 minutes ago, RDgamer64 said:

the last thing that came to mind and i unplugged the gpu power plugs and boot it up.

and gues what it boots up without the gpu plugged to power (but in the pci slot)

Hm, sounds like a power rail on your PSU that supplies the power to GPU crapped out.
You can check it with a multimeter (see if there is a voltage drop when under load, as in when you try to turn the PC ON, just don't short anything!), or simpler (and safer) try with another PSU.
Also if it is a modular PSU check if the cables are properly plugged in on the PSU side.

Don't run that card just from PCI-E slot. PCI-E can deliver up to 75W, R9 380 can draw up to 190W when under full load.

PS I am surprised that you could see the post, usually GPUs that need external power straight up refuse to run if no external power is present.