Unable to Boot PnP fails to complete

I have a machine with a Symbios SCSI card and a Creative SB AWE32 card. When both cards are installed in the machine, it fails to complete the PNP detection. If only one card is installed everything is fine. I have tried to set IRQ's for ISA slots in the BIOS and changed from PnP OS to Non PnP OS but still can't get it to boot. Is there any way to set these cards as non PnP or configure the BIOS to bypass this auto detect? I have even tried shuffelling around different ISA slots but can't get it to co-operate. Any ideas appreciated, thanks.