WordPress calling wrong folder

Hey

I have a problem:

My wordpress files are in a folder called WordPress (yes with a capital W, but not P). If I create a post/page with an image from the media library, the image doesn’t show ond the post, because its url is with the folder name WordPress (with capital W and capital P). The same happens to the read more tag: clicking on the read more button causes the browser to call a url with the folder name WordPress.
OK, these two problems could be solved by changing the blog address to the main url with no folder. (I mean this: https://codex.www.ads-software.com/Giving_WordPress_Its_Own_Directory )
But the problem is arising again, because i want to create a password protected page. When trying to open the page with the password, wordpress calles the wp-pass.php file, but in the folder WordPress, instead of where it actually is, in WordPress.

Questions:
1) Why is this? How to solve it?
2) Will i get trouble just changing the name of the folder to WordPress?

I hope I have made myself clear. And I would really apreciate some help, because this seems to be really a weird problem to me.