Compatible video card isn't recognized, and computer won't startup with it installed.

[mightyfletch]

Just bought a used HP h8 1260t computer that came with a fully functional NVIDIA GeForce 210 DDR3 GPU.  I wanted to upgrade to a 2GB card and checked HP's list of compatible video cards, which included the AMD Radeon HD 7570 2GB video card.  I installed the card, but after restart, the screen stay black and no startup sound happens.  This occurs whether I plug the DVI cable into the onboard video connector or the DVI or HDMI slot in the AMD video card.  I remove the AMD video card and restart to enter into diagnostics.  There is no option to disable secure boot.   I then try to install the old GPU that came with the system, and now it no longer runs either.  I'm not sure what else to do. Any ideas for a solution?  Thank you,

[Prométhée]

Hello

HP Pavilion Elite h8-1260t Product Specifications and Configurable Options
if we look here indeed it is indicated, but
You bought a used graphics card, right?
I guess that should also work, but from this page there are three possibilities of power supply module, do you know what yours is, and what is required for the card buy I saw 250w for some, but not some
now, after what you have done or not, the computer does not seem to work anymore even with the old card, is that correct?

have you tried without any graphics card to connect the screen to the motherboard.?

https://support.hp.com/us-en/product/hp-pavilion-hpe-h8-1200-desktop-pc-series/5187019/document/c028...

[mightyfletch]

The computer and displays work fine when connected to the onboards graphics connection.  However, when the external grapgics card is plugged into the PCI slot, it prevents the computer fron starting up even when the dvi cable is plugged into the motherboard.  In other words, with the graphics card installed, but no cable plugged into it, only to the motherboard graphics connection, it still prevents the computer from booting up.

[Prométhée]

the graphics card should be tested with another computer
either it is defective, or some problem.
the power supply is sufficient?

the bios is uefi or not?

also look in the bios, do you have an option of this type
PCI SERR # Generation
without the card go to bios, deactivate that then install the graphics card