Wheatley doesn't talk at the start of Chapter 5, nor he turns on his flashlight

[OtsoAllioli]

I have a problem. In Chapter 5, at the beginning, when you meet with Wheatley and the lights shut down, Wheatley doesn't talk, and he neither turns on his flashlight. I have gone to a previous checkpoint, and I have also started the whole game again, but it kept happening. I Googled a way to fix it, but it involved the Library games' option buttons (when you right-click on a game and some buttons appear) and those have never worked to me. In fact, not much option buttons have worked for me sincd I installed Steam. So I have 2 problems. How do I fix them?