My partition isn't showing up?

On my Computer, I have two separate partitions set up, but I ran into some significant issues with Windows 7 recently, which unfortunately forced me to perform a complete reinstallation of Windows.
Now that the installation is finished, the system is only showing me the C: partition.
However, when I navigate through administrative tools and open up disk management, I can see that the D: partition is actually there, but it is currently listed as unallocated.
Does anyone know what steps I should take to ensure the D: partition shows up properly within my Computer
?

If you see "unallocated" listed there, just right-click it and follow the prompts to confirm everything—just a heads-up though, formatting that partition will wipe whatever was on it, so you won't have anything left on that specific drive. Once you've finished formatting, it should show up properly in my Computer.

Oh boy, I am in quite a predicament here... all of my files are sitting right there, just out of reach!
I am truly at a loss—what on earth happened? Why is the space showing up as unallocated when it shouldn't have any business being disconnected from the C: partition, especially after I was forced to go through the whole ordeal of reinstalling Windows?

Maybe try downloading a Linux Mint live image, burning it onto a blank DVD, and booting from that—once you're up and running, just see if you can grab the data from that partition.