|The 9400GT is an extremely weak card & in most cases, the 1024MB version is slower than the 512MB version. There's no need for 1024MB on such a low end card anyway. They only do that to sucker people into buying because "more memory is better", right? I hope you didn't buy it for gaming...if you did, you're gonna be very disappointed. Make sure you have the 6-pin PCIe plug connected.|
You should not have disabled in the onboard video in Device Manager. That may come back to bite you. Re-enable it. Then boot into the BIOS & disable the onboard the right way. And look for a setting called "Initial Display 1st" & change it to PCIe. Then shutdown, install the card, connect the monitor, bootup & install the drivers.