I can’t save a video in Windows Movie Maker and also can’t log in to YouTube.

So, I've made a video in the Windows Movie Maker and want to upload it on YouTube. I tried saving it to my computer and it did got saved. But when I run it, there is only audio when I'm sure that I had saved the video. I tried again to save it in a different format and same thing happened. I'm only getting audios and not a single image. What should I do to save the video?

And, I'm also not able to log in to YouTube directly. Even though I enter correct username and password, I get a error message "Invalid username or password"