WD HD no longer shows up on desktop

I recently upgraded my Mac Book Pro to OS 10.6.6 and noticed that my WD 1 Tet no longer shows up on the desktop nor is it found in Disk Untility. Yet, my two other non WD external drives do show up when plugged in. Is there a compatibility issue with Snow Leapord or has my drive just crashed (with all my photos on it)? Blue power light is on and I have tried multiple cords to no avail.

Hi there!!

Can you provide the model number of your drive? o.o