Speakers show as Not Plugged In

Have tried almost all solutions posted and still no sound from Logitech speakers plugged into Dell HD monitor (RealTek High Definition Audio) . Speakers work when plugged directly into pc jack and have always worked when plugged into monitor. Upgraded to Windows 10 and went back to Wondows 7 recently. Any solution will be appreciated. Have tried making sure all is enabled & not muted, updating driver, defaulting to basic audio driver and still no sound. Thank you.

I am connecting the monitor to the pc by HDMI. Speakers are plugged into to speaker jack on monitor -- this is for convenience and has worked for years on this pc and previously on different pc's. Speakers do work if I connect directly to pc and yes, I would need an extension cord. I just do not understand why suddenly the monitor connection setup that has previously worked would stop working and not be fixable. From my searches it seems this is a problem many people have. Any help is appreciated.

Taskbar icon shows white speaker, no red line. When you right click on icon and continue to playback devices, speakers show as not plugged in. Everything is enabled and shows drivers are up to date. Nothing is muted.

While I appreciate your suggestions, what I do not understand is that the speakers were working and I have not changed the HDMI port being used or the default status. This would seem to indicate some type of software issue vs hardware, unless hardware just broke. I see sound levels changing on sound bar graph, but no sound coming from speaker when plugged into monitor. I have not yet had the opportunity to check the NVIDIA driver or the HDMI audio being enabled. Thanks.

Re-installed NVIDIA driver and re-seated HDMI cable. Still no sound from speakers plugged into monitor jack. RealTek high definition audio is shown on several displays but is grayed out and thus not available to select -- this is where speakers are shown as not plugged in. This same situation happened once previously in past 2 years and I cannot remember solution. Speakers have worked fine for 2 years since and then suddenly no sound. Perhaps cause stems from an update issue. The obviously simple solution of a system restore is not available for me as I lost my restore point history when I upgraded to Windows 10 and subsequently downgraded back to windows 7. I will probably purchase an extension cord and plug speakers directly into pc, but I still just do not understand what has happened to cause no sound through usual setup using speaker jack on monitor. Thank you again for your involvement and suggested solutions.