Win98 keyboard power buttons not working

My apologies in advance if this has been asked and answered already, but I've spent hours searching to no avail on this specific problem:

For over a decade I've been using cheap so-called Windows98 keyboards with the 3 power button set to turn my rig on and off. Whether the sleep and wake keys worked I can't say because I don't remember ever using them. But recently, I installed 98SE on a P4C800-e and find that both the power as well as the sleep key put the machine into standby mode, or simply don't work at all, depending on which settings in BIOS I twiddle. I've already tried several keyboards of different makes and model, all of which work as expected when using XP. The original machine was built around a Soyo SY-6BA+IV with Award bios and a BX440 chipset while the newer P4C800 has an AMI bios and 875 chipset.

The real question is if anyone around here has gotten the power key on the keyboard to work in win98SE on a P4C800 or similar mobo.

For completeness, PSU is an Enermax 720W Infiniti, no SATA drives currently attached, the only PCI card is an internal 56k software modem. Also, I've already perused the MS articles on shutdown issues. Still, there must be something I've missed.

Any help or advice would be greatly appreciated.

Thanks,

bob