Graphics Card no longer being recognized

[DitR]

I had 4 monitors working perfectly on my pc until after this past weekend. I have 2 monitors that are attached to a GeForce 8400 GS that are working, but the other two are not working. The drivers for both of the other video cards are no longer recognized by windows 7 even after reinstallation (drivers cannot be found in device manager). Any idea on why the computer and BIOS are not recognizing the video cards they once used? Also, the computer and monitors were on over the weekend. The other two graphics cards are the ATI Radeon B276, and the ZOTAC GT218IONGPU-A-E

 

[hang-the-9]

Test the cards in another computer, that will let you know if they are still working or not.