Permalink issue

Hi there!
I saw that this issue is quite often, and I tried several steps that worked for other users and nothing happened.

Let me detail my issue:

I have a gadget news website, so I created pages like news, how to, and so on. The problem is that if I change the default permalink it will give me a 404 error page, but if I let the default permalink, it shows me the created page.

I would let it like that if there wasn’t a problem with deault too. If I write a post about a specific game launch, for example, I chiise both news and games category, but it seems that only my Home page will display it.

This is my .htaccess file:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

I guess that once i fix the permalink issue, the posts will appear in the required pages that I selected.

The custon permalink I want to use is: /%category%/%post_id%-%postname%

Would this have something to do with my host or wordpress? If anyone can help me, I would like step by step instructions, as this is the third day that I try do do something about this and I am very confuzed.

Thank you very much!

[No bumping, thank you. If it’s that urgent, consider hiring someone.]