Well finally I have solved the problem. And surprise, surprise It was the freaking UPPERCASE letter in my table prefix. I had it this way in my wp-config file wp_C5n but for some reason most of the tables got a prefix wp_c5n. But not all. So what id did was I changed my table prefix in wp_config file to all lowercase and then went through all the tables by hand via phpMyadmin to see If there’s any uppercase tables left. There where about 3. They were inside usermeta table and inside options table. Now finally everything is working.
Did a quick search through wordpress codex but did not find anything mentioning not to use uppercase characters.
