There is No Media to Preview - Need answers! HELP!

I have used Photoshop 13 for years.  I have over 30,000 pics and videos files.  All worked fine until 2 days ago.  Now I am getting a screen that says "There is no media to preview".  Not being very tech-y, I don't want to start clicking buttons until I know what I am doing.  Don't want to make it worse. I haven't changed anything that I know of. (The only odd thing that has happened lately is when I tried to upload pics from my husband's iPhone 6 to Photoshop, it would not retrieve them. That operation had been working fine in the past. Don't know if that would have any connection to this problem or not.)  I am using Windows 10. I'm feeling pretty desperate to retrieve these pics.  HELP!