replaced gpu not working ?

[I3ennn]

alright so, i recently replaced my gpu by sending it back to sapphire and they sent me a new one. i sent it back because none of the fans were spinning and the hdmi said no signal (it was an R9 380) and now i have the new one i plugged it in and the fans spin for maybe 2 seconds then turn off and they come on and spin for a short amount of time again. i get a signal from the GPU because i can see the bios but after that my monitor just goes blank. i reinstalled my very old graphics card and it works like a charm. I dont really know what is wrong but i was thinking maybe the power supply is not working properly ?

 

[hang-the-9]

Need full system specs, including the power supply brand and model.

 

[I3ennn]

Need full system specs, including the power supply brand and model.

I have a corsair cx750m power supply with a gigabyte motherboard I'm not too sure of, a fx 6300 processor, 8gb Kingston ram and a western digital 1tb hard drive. And I used to be running the r9 380 but now I'm using a amd Radeon 7770 1gb

 

[hang-the-9]

Before swapping the card, do a BIOS update if there is one, make sure all power plugs are in the 380. The CX is a lower end model from Corsair, if you can find another system with a good power supply to test your video card, that would be a good start.