First, please double check your VGA card whether support UEFI mode or follow the steps as below :
1. Turn OFF your system.
2. Remove the VGA card, then conntect your monitor into onboard VGA or DVI port.
3. Power ON your system, then press [Delete] key into BIOS Setup Menu (CMOS).
4. Select the option as Boot > CSM Support > change the option from [Disabled] to [Enabled].
5. Press F10 to Save configuration and reset.
6. Turn OFF your system, then install the VGA card.
7. Please connect your monitor into VGA card, then Power ON your system.
And it will work.
