ATI Radeon 5850 not being detected

[amurdoch]

I just purchased a Sapphire 5850. I installed it in my mobos PCI-E x16, but my computer doesn't seem to detect it. It won't post with it as the only VC. All power cords are installed and the fan runs when the system is booted. I used to have an 8800GTX, and the system will work with the 8800 by itself or with the new 5850. When booted with the 8800, I went into the device manager and I didnt see it detected. Furthermore, I tried installing ati drivers and they werent able to find the card either. Even more strange, I was able to get my system completely working once with just the 5850 (got to windows and typed pw, etc). There was no display but i was able to hear windows coming alive.

I have a ASUS p5n32-SLI SE mobo. If anyone has any ideas please let me know

 

[EXT64]

Did you uninstall ALL (driversweeper, etc) of your NVidia drivers before installing the 5850. You can also try booting in safe mode, as that will use the default MS driver.