external firewire drives won't mount
I have had 2 Western digital Mybook studio 1TB external drives connected by daisy chain to one another via firewire 800 for a long time and it was working fine until today....now suddenly neither of the drives can mount/be recognized by my Imac 2.8 Ghz Intel core 2 duo 24" running OSX 10.5.8. I have tried firewire 400 and 800 on both drives, tried disconnecting everything, restarting/rebooting, resetting PRAM, verify disk, repair permissions, different cords....nothing works. USB portable drive is still recognized fine---must be a firewire thing? Any advice appreciated and welcomed, I am at my wits end as these drives contain my last 3 years of photography and design work and i now can't access anything. HELP!
thanks in advance for any help,
kate
imac g5 24" 2.8ghz intel core 2 duo/macbook pro 15", Mac OS X (10.5.8)