How to determine if a graphics card is compatible with a computer?

Question

Video cards

Good day.
I recently purchased a 4-out video card from amazon and tried to connect it to an HP computer.
With a new video card, the computer did not turn on.
Both the computer and the video card are new, I can’t understand what’s the matter.
The video card works on a PCI-Express port and the computer has a PCI-Express port.
I would be very grateful if you tell me the reason why the video card is incompatible or not suitable for this computer.
VIDEOCARD
ATI FirePro 2460 512MB DDR3 4x Mini-DisplayPort Low Profile PCI-Express Video Card 100-505610
www.amazon.com/ATI-FirePro-Mini-DisplayPort-PCI-Ex...
COMPUTER
HP Pro 3500 Microtower PC CPU Intel® CoreTM i5-3470 •3.20GHz, 6Mb
cache, 4cores/Intel® H61 Express/DDR3 SDRAM 4Gb (1333MHz) 2slots/HDD 500Gb 7200rpm SATA/DVD±RW SuperMulti
SATA/Intel HD Graphics 2500/slots: 1*PCIe x16; 3*PCIe x1 ; 1*mini PCI/Ports: 10*USB 2.0(4 of the 10 USB 2.0 ports are
internal); 1*RJ-45 RTL8171E(10/100/1000Mbps); 1*DVI-D; 1*VGA; 1*headphone; 2*microphone; 1*audio in; 1*audio out/PS
-300w(aPFC)/FreeDOS

Answer 1

How many watts is the power supply? If this happens, then most likely there is not enough b / p power, and if the video card has an independent power supply, then it must be connected.

Answer 2

Do you have a 300 watt power supply on your computer?
300w(aPFC)?
If yes, then it is logical to see which blocks are advised to use with such a vidyukha.

Answer 3

I found the problem :=) The problem was in the adapters, or rather in their number :=)
The Mini-DisplayPort video card, and VGA monitors, ended up using two adapters, the first Mini-DisplayPort to DVI, the second DVI to VGA.
I don’t know why, but not a single monitor turned on ... interestingly, this circuit worked on another video card :D
PS There was no place for a separate power supply on the video card, but the computer power supply was replaced, put on a more powerful one.