My sister's kitten was in my room the other day and stepped on my surge protector, which was where my external HD was plugged into.
I got the Device Removal warning on my iBook, no big deal, sometimes the power cord has gotten knocked out before and turned off. I turned the HD back on, and the blue light is on and everything is plugged in and secure, but it's not showing up on my Mac.
that cat pic was really funny..... seriously though, check and see through device manager if you can see the drive as a system component... if you can, go into disk managment, Right click on my computer, manage, disk manager and see if it shows up there.... maybe its there but has no drive letter... assign one and boom. I see this all the time with memory sticks...
If it's new, it probably needs to be formated....Go to the control panel >> Admin Tools >> Computer Management >> Disk Management...
It should show up there....Then you just need to right click it and hit format.