So I uninstalled my Nvidia 7800 gt oc for my new powercolor ati 5770 radeon HD card. The PC starts up but my monitor does not. When i try my nvidia card again it works fine. And yes I have got rid of all the nvidia drivers previously installed by going to devmgmt and wiping them out. Here are my PC specs.
Board: ASUSTek Computer INC. LITHIUM 1.04
Bus Clock: 200 megahertz
BIOS: Phoenix Technologies, LTD 3.08 09/12/2005
You can install the ATI drivers with the nvidia card in. When you get the ATI card working, uninstall the nvidia drivers if you have issues. I've read that they don't like each other with certain settings. Good luck.
Sorry. Lack of drivers won't account for it not working in boot/bios. You should at least get that. Still guessing its a PCIe 2.1 card in a PCIe 1.0 board. It will fit, but it might not work. Either return or install newer bios to see if that fixes it.
I guess I'm done helping in this thread. If you're not going to answer the questions, there isn't anything I can do.
My best guess based on the available data is the card doesn't support your motherboard. Not because its an AMD/ATI card, but because it's a PCIe 2.1 card and you have a 1.0 board. Yes, it will fit in the slot. But not all 2.1 cards work in 1.0 boards. If you want to get a signal, return the card for a 1.0 or 2.0 card. That or update your board. Good luck, I'm out.