Well I don't have a mobo guide and I've been into my BIOS but no option to disable my onboard. I contacted my manufactuer but they sent back saying my mother board wasn't there brand.
Help
heres all my info.
BIOS ID: 63-0302-000000-00101111-060204-I915-A0005035
OEM Sign-On: BIOS Date: 06/02/04 21:38:00 V
BIOS Date: 06/02/04
BIOS Type: AMI
Chipset: Intel 2580 rev 4
Super I/O: Unknown
OS: WinXP SP2
BIOS ROM Socket: Unknown
BIOS ROM Size: Unknown
Memory Installed: 503 MB
Memory Max: Unknown
CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz 2800 MHz
Let me ask you a question when you put in your new graphics card do you run your monitor through your old onboard graphics card port or the new one when you start up your computer. If you put it on the old port then switch it to the monitor port on your new graphics card. The display mite be kinda bad but it will improve once you install the correct drivers for your new graphics card. Windows XP will automatically recognize that there is a new video card on the agp slot when you install your new video card. Let me know if this works for you!!