Welcome to the community, @Bobby!
I'd strongly recommend you consider a professional data recovery company for assistance with the files, if they are so important to you. Any DIY attempts could potentially do more harm, than good. I'd second what @hang-the-9 mentioned and check how the HDD is detected on another computer internally via a different SATA cable and externally through an enclosure or a docking station.
You might also want to try swapping the SATA cable and the port where the HDD is connected to on your PC as well and see if that will make the HDD recognized in Windows.
Be careful because any additional stress on the drive could be fatal.
Keep us posted!
SuperSoph_WD