Welcome to the forums, simmyjiff.
WMP => Alt => File => Open (Ctrl-O) => Navigate to your drive to open a media file, does it appear in windows explorer ? Do your see it when you open My Computer?
You should be able to add it to your library this way:
1. Start WMP
2. Switch it to library view (WMP has a special icon for this purpose - Right Bottom/Top)
3. Click on Organize on the top menu bar, click on "Manage libraries," and then choose the library to which you'd like to add a folder.
4. Next, click the "Add" button to browse for a folder and add it to your Windows Media Player library. You can select a folder on your local computer, an external USB hard drive, or even a networked location like another computer in your homegroup.
When you've chosen your folder, click the "Include folder" button.
5. Click "OK." It may take a few minutes for Windows to add and index the folder if it contains a lot of files.
You've now added a folder and all it's media files to your Windows Media Player 12 library. Continue to repeat the process to add more folder to your Media Player libraries.