Computer doesn’t recognize external hdd anymore.

So I’m running Windows Vista. I’m using a Western Digital Elements 1TB. When it’s plugged in, my computer will see that it’s plugged in (the option to remove hardware safely pops up in the system tray), but it doesn’t show up in My Computer.

I tried it on my sister’s laptop and got the same results (she’s running XP, though. Don’t think that makes a difference, but I thought I’d throw that in there).

I right-clicked My Computer > Manage > Disk Management and it shows up as Disk 1, which is not initialized. I would think that it had to be initialized (meaning enabled or something) to work, and I selected that option to see what instructions it gives me for it, but I’m not really sure what it’s telling me to do next and I don’t want to do anything. (See the attachment).

Any ideas?

Thanks.

Edit: I tried plugging it into another USB port, the one I always have my mouse plugged into and it didn’t work. Oddly, the mouse stopped working when I plugged the HDD back into its original USB port and didn’t start working until I disconnected the HDD again.