Complete hard drive failure questions

[dareutwo]

Morning all -
I get to the computer this morning, and it's saying can't find Y:\ something or other.
I've never seen this message before, so I simply reboot.
After the reboot, I can't seem to find the other hard drive on this machine.
It used to be set up with 2 hard drives.
C: D: and E: (which is what I'm using right now)
And the other drive Z: Y: X:
I'm guessing that this second drive probably crashed, but I'm not sure how to test it, or if there is some way to try and find it?
If the hard drive did indeed crash, anyway to get the info from it? It's nearly all backup info, but some important work stuff is on there too.

Let me know what other info I need to post so you understand what I'm trying to convey.