PCI Express card

Hi Everybody,

Thanks for your time.

I have a Dell Optiplex 755 computer and I am trying to put a PCI Express card, (It’s a customized one for
some particular data transfer which follows the existing PCI Express standards).

I put the PCIE card on the system and tried to boot the computer there is no response from the system.

There is no LED blinking red on the motherboard.
No ?beep? sounds on the system.
It just hangs like that.

I removed the card and tried again booting the computer, it boot normally.

I checked in the boot (F2- Windows Setup) and analyzed the Options for the PCIExpress slots and all slots are active and available.

Can anybody help me in resolving the issue.