(Have not read the previous pages of this thread...so excuse if I duplicate stuff)

-> missing vendor specific gpu driver
-> no (or up to none) hw acceleration
-> issues with OGL/D3D
If it is an IGP (chip on the mainboard) then install mainboard drivers.
If it is a GPU card, install drivers for the GPU.
When booting up your computer you most often see the GPU chip name on the top left of the screen - before mainboard information ("bios post messages" or "mainboard logo") is displayed.
Internal IGP: you connected your screen to a cable socket right next to USB and audio sockets.
External: there are some metal slots below the usb/audio/whatever-sockets (90 degrees turned compared to the alignment of these mainboard sockets). One of these slots (or two..) is occupied with your screen-cable-socket (and hdmi and so on).
Hardware can get identified via the "vendor ID" of the chip - which Windows exposes. But as this is a more complicated job, I would postpone that for later.
bye
Ron