|And is the card actually a PCI card or a PCIe card? Big difference. If it is a PCI card and you have integrated graphics on the motherboard both can work at the same time. But the integrated would remain the default display. Therefore you need to keep a monitor connected to it. |
The way around that is to try disabling the integrated graphics in the BIOS screens and to choose to boot to PCI display first.
Failure to provide any hardware specs makes it necessary to guess.