http://www.ati.com/support/infobase...leshooting.html
其中這2個ISSUE可以試試看
Issue with the system BIOS or its configuration

In some instances an updated system BIOS or altering the Plug & Play (PnP) settings in the BIOS may be required to allow the graphics card's BIOS to initialize correctly for support of DVI Flat Panels. Please check the following:

1.Ensure that you have the latest system BIOS for your motherboard.
2.Toggle the PnP aware OS option in your system BIOS from yes to no.




Conflict with USB support from motherboard

In some instances the graphics card's own BIOS may not initialize correctly due to how USB support is implemented by the system. When this occurs the card may not be able to correctly support DVI panels, especially under DOS. Try the following:

1.Disable all USB support in the CMOS SETUP and retest.
2.Disable LEGACY USB support in the BIOS and retest.
3.If you are using a USB keyboard or mouse try testing with a PS2 style
keyboard and mouse