Do you have an entry 'acpi' in bios? if so whats it set as ?
& if you open device manager & view 'computer' by resources, if you look at the IRQs are there any entries sharing ?
What is the actual message on the properties of the erroneous 'PCI System Management BUS' ? {I pressume the message on the 'multimedia controler' is something like no driver or such ?}
Can you confirm whether this machine has been to
Windows update site or not please ? (this is a different lot of updates to intel, this is s/w updates to 98 @ M$)