audio, but no picture

[Ddan]

I'm using a Win7 ThinkPad. I tried version 21 and got no picture. I uninstalled then installed ver 18 (based on tip). Same result, black screen WITH sound. Probably not finding correct drivers. What is wild is that the part of the YouTube video is buffered so that I don't have to be online to see and hear the beginning. Wish I could somehow extract the whole thing using my browser by enlarging the buffer. (the video is nearly 50 minutes).

 

[Ddan]

side topic addendum: When I slide the cursor for the YouTube video (in the browser, not OBS) while offline, it seems like it is all there. Is it only stored in RAM? I can't find anything in the Opera or Windows folders. I always keep hidden folders and files visible.