Basim_ :
does that my motherboard is incompatible with my gpu?
It won't say. To be compatible, it only needs a PCIe x16 slot and a BIOS that can get along with the card's UEFI. If your monitor is plugged into the card (and not the m/b's port) and it is producing a display, it is compatible.
Did the new card come with a disk? If so, there should be a driver on it. If not, follow the directions to download the driver on the link InvalidError sent you.