Exclude a specific category from the Blog page template

Hello,

I would like to know how to exclude a specific category (#4 or “Services”) from the Blog page template.

I have tried to follow both these instructions: http://codex.wordpress.org/The_Loop#Exclude_Posts_From_Some_Category

as well as those I found here: http://codex.wordpress.org/Class_Reference/WP_Query

but had no luck: the blog page template selected keeps showing all of the categories.

I have succeeded in having a page displaying only a specific category, but I couldn’t exclude a specific category.

Would anyone help me, please? Thank you so much!