my computer won't start. The error can be described as follows.
1) At startup, the computer emits the usual startup sound. The sound is then repeated every three seconds. The Apple logo is not visible, and the screen is black.
2) Start without a graphics card is followed by the usual startup sound. That is, no signal was every three seconds this time. The Apple logo is not visible, and the screen is black.
Attaches a video on how the computer sounds.
Model: Mac Pro 5.1 Grid mid 2010 (A1289).
Operating System: Mac OS X Yosemite 10.10
What might be the problem?
Feel free to tab in with your own little theory;
Serial No: CK0420S1H2P
Graphics Card No .: ATI RADEON 5770 original