LrC won't play videos

LR Classic 11.3, 11.2, 11; Windows 21H2, Dell with 6 cores, 3.19 GHz, 32 GB SSD. Problem began back in LrC version 10 and earlier Windows versions.

LrC won't play any videos. They all run normally in VLC and other video players in this and former Windows and LrC versions. Trying to run any video results in an error message saying "Dynamic Link Media Server failed to load." That app and its several supporting programs appear separately in File Explorer for Bridge, Lightroom Classic and Photoshop.  Message continues saying restart Lightroom etc. none of which work. This video outage began before several updates to LrC, so that proposed solution isn't valid. I don't remember any incident or update/upgrade that may have caused this.

I understand that these programs were written by Adobe, not Microsoft, although there are such programs elsewhere with the same name not written by Adobe. I have to just apologize to my students for this inability to teach them how to use videos, in addition to not viewing them myself.