Hello Taterbiscuits,
Please check out this link, which will guide you through the correct process to import media from a computer to iTunes on PC, so we can make sure there aren't any issues there: Import media from a computer to iTunes on PC
Import media from a computer to iTunes on PC
If you have audio or video files on your computer, you can import them into iTunes so they appear in your iTunes library.
To add media from Audible Manager to your iPhone, iPad, or iPod, you need to first import it into iTunes.
Get media into iTunes
1. In the iTunes app 
on your PC, choose File > Add File to Library or Add Folder to Library.
2. Locate a file or folder, then click Open.
If you add a folder, all the files it contains are added to your library.
Tip: You can also drag a file or folder from the desktop to the iTunes window to import it.
When you import an item by dragging it to the iTunes window or choosing File > Add File to Library, a reference (or “pointer”) to the item—not the item itself—is placed in the iTunes folder. You might not be able to play songs if you move the references to them.
Copy items to your iTunes folder when you add them to your iTunes library
You can set iTunes to place copies of items imported into iTunes in the iTunes folder.
1. In the iTunes app on your PC, choose Edit > Preferences, then click Advanced.
2. Select the “Copy files to iTunes Media folder when adding to library” checkbox.
The next time you add an item to your library, iTunes places a copy of the file in your iTunes folder; the original file remains in its current location.
If you want items to appear in iTunes but also remain in their original location, deselect this checkbox. For example, you can keep music imported from CDs on your computer and save your video files on an external storage device.
Tip: When you drag files to the iTunes window, you can temporarily reverse the checkbox setting by holding down the Alt key while you drag.
If the file is an unprotected WMA file and you have Windows Media Player Series 9 or later installed, iTunes makes a copy of the file and adds it to your iTunes library. The original WMA file remains unchanged. You can’t add protected WMA files or protected WMV files to iTunes.
To learn how to add other content to iTunes, see How to add items.
If you need additional assistance, please contact Apple Support for help. You may be able to reach them here: Get Support
Thanks!
