[NAME]​  - The (covered) onboard HDMI port won't be active when an add-in video card is installed unless you (1) enable the Intel Multi-Display option in BIOS setup, and (2) have at least one monitor connected to the add-in video card before you connect a monitor to the onboard HDMI or DP port.   Is that adapter connected HDMI(video card)>DVI(monitor) or DVI(video card)>HDMI(monitor)?  There are many different "flavors" of DVI ports, so are you sure the adapter is the right type for your cable and monitor input?   
Looking for a way to reload (or verify) BIOS on XPS 8700.   I was rooted while running Linux ever since have had problems booting. Can't access BIOS setup, no Dell logo on boot.  Have REPLACED hard drive, cleared CMOS (rtcrst) & PSWD Pulled CMOS battery. Tried to access BIOS w/o hard drive.  Dell logo only shows once out of +- 30 boots. Have also checked & replaced CMOS battery.    W/O BIOS access can't force USB boot etc etc.  F2 / F12 only work when Dell logo shows.
XPS 8700, BIOS verify or re-install?