External Hard Help

I have a WD passport EHD and I am trying to take some old file off of an PC that isnt used much anymore.

When I plug the HD into the PC I hear the sound the computer makes when a HD is connected but I cant seem to see the HD on the PC

Its been a while since I really have played with the PC and may have forgotten a few thinks about dealing with PCs but it should be pretty straight foward.

What should I be looking for or how can I tell if the PC is reading the HD?

Thanks