Hopefully someone here can help me resolve an issue with a new Sapphire HD 4550 graphics card that I installed today on my Acer desktop. When I boot up the system with the card in the PCIe slot, the computer starts and then nothing else happens. Nothing comes up on the monitor so I can't access the BIOS. Before installing the card I tried disabling the integrated graphics card (Radeon X1250 on an Acer F690GVM motherboard), but I couldn't find anywhere in the BIOS to do this or a jumper on the MB. Therefore, I disabled it in Windows Device Manager and uninstalled the drivers.
I managed to get Windows (Vista 32-bit) to recognise the Sapphire card and install the drivers, but only if I set the BIOS to load the onboard graphics by default. Under these conditions I can see the fan on the Sapphire turning. If I then restart the computer and reset the BIOS to load the PCIe graphics card by default, the system stalls on start-up again.
I am wondering how I can disable the onboard graphics because this might be the problem.
My system has an AMD Athlon 64X2 dual core processor with 2 GB RAM and a 300 Watt power supply. The PCIe slot worked fine with the NVIDIA 8500 GT graphics card that I tried recently (which I returned and replaced with the 4550).
Any ideas how I can get this card to work?