I had the same problem.
Reformatted a PC id got hold of to find the video controller had a yellow question mark in device manager.
Its not a removable graphics card so I had problems identifying it.
Tried a few motherboard and pc names and numbers but got nothing useful.
In the end I installed the driverguide toolkit.
Ive heard other people have used Everest
They push their fee paying update but it identified the manufacturer of the hardware for me, which I then googled to find a good driver quite easily.