You didn't pay attention to the last part of the post:
Quote Originally Posted by Boki_Srb View Post
...but didn't you select something that shouldn't? Maybe "Default Thread Age Cut Off".
Options that you set yourself.

This particular one:
Top of the page » Settings » left menu » My Account » General Settings » Thread Display Options » Default Thread Age Cut Off
select "Show All threads", click button "Save Changes"

Or just use Reset Fileds button at bottom