In that case, I'm not sure of the best way, but I can think of A way.
You could use the Terminal to get a text list of all the files in a particular folder, using:
cd /volumes/[your hard drive name]
followed by the path to the folder you want. (If there are any spaces in the names of folders in the path, they must be preceded by a "\").
Once there, enter the command "ls" (that's a small L, not a capital i) followed by Enter.
The list of files should appear in the terminal window, and you can copy them from there and paste into your spreadsheet.
If the list is too long to select in one screenfull, I think you can save the terminal output to a text file.
(Sorry if I'm forgetting a step - I'm on my phone instead of my computer, so I can't go in and check the specifics right now.)
Let me know if that does what you're trying to do.