PC won't start after new R9 270x installed and case led blink

[igtaba]

Hi guys, I'm in a very big problem, yesterday a guy bring me a pc and a new Sapphire R9 270x, and wanted the instalation of the new card and a new case sentey halcon II. After I clean everything in the old case and put it in the new sentey case, and installed the graphics card, I tried to start the PC but anything happend, immediately after I plug the power chord to the power supplier the leds and the fan turno on for a sec, and blink twice, and dont let me turn it on, and if I switch for the old graphics card (a radeon HD5xxx series) the computer starts well
I wanna know if it's is a power supply problem or that the graphics card it's death, can you help me?

Specs:
Case: Sentey Halcon II (new)
Graphics Card (new) Sapphiere R9 270x
(old) Radeon HD5xxx series
Mother Asus
4gb RAM
Power supply: sentey 700w
500gb WD caviar green HDD
sony DVD-RW

Thanks a lot, excuseme for my bad english, and thanks again

 

[T_T]

How many times have you tried installing the new GPU? I ask because if you gave it only one attempt, you may not have seated the GPU snugly enough, which could have caused a short circuit. Try this:

1. Take motherboard out of case
2. Place motherboard on cardboard or newspaper, or any non-conductive surface
3. Install the 270; the PSU; and one DIMM
4. Turn on power to the motherboard by using a metal object to jump the PWR_SW pins (touch both pins with the metal object. Do it again to turn off power)

Does the PSU turn on now?

 

[igtaba]

You think that I could have broken the GPU? I don't think, it was installed good I think, tomorrow I would try this solution you say, and I think I would try the 270 in other computer I have at work, because I thinks that if works on other computer the 2070 then it might be a problem with the PSU. Because the computer wirks when the 270 it's not plugged