I can't modify the template i assigned to the Posts page (Wordpress)

Answer 1

Here are a coupple of links that I think will help you:

http://codex.wordpress.org/WordPress_Lessons#Customizing_Templates
http://codex.wordpress.org/Template_Hierarchy

I have a few questions:

1. Why do you have the same code in both tempaltes? Frontpage will never be the same as a single post.
2. Why do you choose to use blog.php instead of single.php? When you open a Post, WP will automatically use single.php.
3. Have you sett in settings which page should be the front page?
4. If you are creating a template, then you must have template name at the top of the file (missing in blog.php)