net123 in a post dated 6/21/03:
Changing resources in W2k is not for the impatient.
You must reinstall W2k. You can do a repair install, but there are a few more reboots than the standard repair type install. I am pasting below, the contents of a post of mine from some weeks ago. Please excuse any verbiage that does not apply to your specific situation. BTW: I had problems with my AHA-2940U2W and Adaptec is in complete denial about this issue, or at least was in denial.
/*Begin copy -- to end of post. Regards, Mike
Welcome to the world of ACPI. Windows 2000 will install full blown IRQ sharing if your BIOS is dated newer than 01/01/2000 automatically and by default.
The only way to change your IRQ is to remove ACPI. The only way to remove ACPI will take an afternoon.
First, have your Windows 2000 CD and all the information about your peripheral card that you can gather. The more info you get, the less experimenting you will have to do.
Here is the process:
PCI devices today are loaded with IRQ presets. Manufacturers have agreed to use certain IRQs for their devices. For instance sound card traditionally used IRQ 5. Unfortunately, Sound Blaster decided to break this habit, my current SB uses IRQ 12.
Your problem now is the very real possibility of IRQ conflicts - depending on your setup.
The most extreme manner of sorting out IRQ issues is this:
Remove all peripheral cards except for the video card. Boot Windows 2000, open Device Manager and set this card to use the desired IRQ. Shut down and readd your cards one by one, rebooting between each and setting the IRQ for each - or just accept where Windows 2000 slots them. You only care about the video card it seems.