PC won't boot after installing new card

[JoeDvine]

Ok so i just got the MSI r9 280x twin frozr along with a Corsair CX 750w Power supply But i cant get it to boot with the GPU, my old r7 260x works but the new card wont, i am sure i connected everything ok, when i put the new card in, my motherboard beeps once then 5 seconds later it beeps again with no display and not much noise either and i have no idea why, can anyone help?

The rest of my specs are..

CPU - Fx 6300

Motherboard - Asus m5a78l-m/usb3

Ram - 8Gb

PSU - Corsair CX 750w

Also this pc came was already built when i bought it.

 

[greens]

It is a driver issue.
Using the old card, uninstall all AMD drivers and CCC.
Download the newest drivers for your new GPU and install them.

Shut down, swap the GPU, and boot it up.