I have a fresh install of Windows 2K3 R2 on my Dell PowerEdge 2850. I got the OS up and running without any problems, and then popped in my AJA LHe PCIe card. For those unfamiliar with the AJA card, it is used for encoding and decoding in video editing.... but that should be irrelevant to my problem since there is nothing even coming up in the device manager as an Unknown Device.
Figure A-5 from Dell's website here: http://www.mohca.gov.bt/~susumu/other/dell/2850/data/pe2850/doc/en/it_en/t1393aa0.htm#wp1041040
shows the PCIx 4x-lane slot, which I put the card into (it is also 4x). Just for fun, I put the card in the 8x slot too, which the system also did not recognize.
So I'm out of ideas. I checked the bios, all the startup hardware configs, etc... I can't find anything that will seem to "enable" anything plugged into the pci riser card on my PowerEdge.