1) Does the PC produce a display and boot when the monitor is connected to the integrated video output from the MB?
2) How are you connecting the card to the monitor... DVI to DVI, DVI to VGA, VGA to VGA, HDMI to HDMI, ...?
3) On some older Dells (about that era) you needed to go into BIOS and manually select the PCIe X16 slot instead of the integrated video. They didn't auto switch like boards do today.