Thank for your reply!
1. I checked the link to YouTube help where it shows that it supports 5.1, but does it support 2.1?I did a search but could find nothing about 2.1 audio in YouTube Help. I've tried changing the setting on the computer's audio output from Stereo to 5.1 Surround. When I test the speakers while still in "Speaker Setup," there is no sound when it says it's testing the sub-woofer.
I ran the 2.1 Speaker System Test that you referenced in #48 of this thread.
When that YouTube video shows it's testing the sub-woofer, there is bass coming from my sub-woofer but also from the stereo speakers. There is never an instance in any tests I've tried where sound is only coming from the sub-woofer and not the stereo speakers. That would be expected, I suppose, because I have selected Stereo in "Speaker Setup" because there is no option for 2.1 audio and my sub-woofer doesn't pass the test for 5.1 Surround.
2. The speakers are properly connected, from all I can tell. I have not yet tried the speakers on another computer but that's my plan. I will update the result when I do.
3. Regarding the Realtek HD Audio Manager, I had tried searching for it from the start bar but found nothing.
4. I tried looking for the Realtek HD Audio Manager in the x86 Programs folder, as you suggested, but it only had things for the Realtek card reader.
There is a folder for Realtek audio in the other Programs folder, but any applications I click there either seem to do nothing or they take me to Dell's audio manager.
I was quite certain that when I started troubleshooting this, I had the same Realtek HD Audio Manager dashboard on my screen as the one in your screen shot at the beginning of this thread. Maybe I'm mistaken.
Whether I can find that dashboard or not (although I wish I could), my biggest question is how to get sub-woofer audio independently from the stereo speaker. Do I need a different driver, perhaps, that will allow "Speaker Setup" to include 2.1 as one of the options?
Thanks for helping me try to figure this out!