I really appreciate your reply. To confirm your suspicion, I uninstalled all software and drivers related to the Matrox Mojito card and uninstalled the card from the x16 full slot. I then installed the NVS300 card into that x16 slot (Slot 1) and the server booted and used the NVS 300 card just fine.
I then tried to move the NVS 300 card back to the PCIe 2 x8 (slot 2) on the riser, and nothing...
It appears that for whatever reason, this server will not allow a graphics card to be installed in anything but the main PCIe x16 slot. It seems strange to me because the NVS card meets the requirements of Slot 2.
In regards to video card performance, it isn't a big deal. I only need the video card to give me a little more horsepower to aid the Matrox Mojito card's ability to do its ingest and encoding of a video stream. I am not relying on the NVS card to provide superior performance of video display output.
Either way, it looks like I am stuck unless I can find a way to force the Slot 2, PCIe 2 x8 connection to allow the NVS to work.
I have been digging through Firmware updates, IRQ settings, PCIe settings in the BIOS, etc. to find an answer, but it appears I am out of luck.
Thanks for your thoughts!