Renpy can be picky,
there was another thread like this a while ago where some different possible methods to fix were listed, give those a try. The last post about headphones is a little weird.
OMG! I mean like OMFG! You are not gonna BELIEVE this!!!
You see, shortly before I encountered the problem, I moved the computer desk. At the same time, I threw out the old system speakers because they were crackly and didn't work right anyway. Never much gave a poop about the audio anyway, so until I came up with something, what the heck.
Then...and somehow I never put the two together...I lost my animations.
I made this post, got the suggestions, which I had suspected were the right things to do, and have been pounding the websites, downloading drivers, trying this and that, to no avail. Finally, I'm ready to give up.
THEN I READ YOUR LAST POST.
I didn't go anywhere else, I just sat here and said, you're freaking kidding me...it couldn't possibly be...
So I plugged in a pair of headphones.
My animations have returned.
Excuse me now, I'm going to go pound my head on the wall while laughing hysterically!