I've had this problem for some time and have found no solution and it is REALLY annoying.
I use an old IBM-style buckling spring keyboard such as this one
I in fact DID use the original IBM keyboards and tried two of them that I was kindly sent by people who had them lying around. I since ordered a customised 105-key one with the Windows and context menu keys and HOPED that, as it was a new board with a lilac-coloured PS2 plug, the problem would go away, but it didn't.
The problem is as follows:
1. If I enable the boot menu for a dual-boot XP / W2K system, the keyboard doesn't work to allow me to choose a menu item.
2. If I accidentally boot with a floppy in and get the "non-system disk - press any key" message, the keyboard doesn't work.
3. If I boot from a CD-ROM and get the "press any key to boot from CD-ROM" message, the keyboard doesn't work.
4. If I try and enter the Norton Ghost serial number to Ghost an image, the keyboard doesn't work.
It DOES work in the BIOS; it also works at the initial stage of bootup when I can select the boot menu etc. It also works to allow me to F8 the Windows Boot to get the Safe Mode etc. menu.
So when I'm reinstalling an OS or working with Ghost etc. I have to keep digging out my other keyboard (MS but also worked with crappy Evesham OEM) and plug it in and it works.
I've hunted the BIOS settings but there's NOTHING that works. Any ideas?
My mobo is Gigabyte 8-ITX with Amibios.