Posting pages / articles

Hello,

The editor is not showing properly when I want to add a new page or a new article. All the buttons and the shortcodes has dissappeared and I’m seeing only the buttons of the text version.
I had many problems with my WordPress lately. When I try to fix an issue, I get another one.
I reset all plugins, re-installed a fresh copy of wordpress, tried the Twenty Eleven” Theme, cleared the cache… but nothing.
Please help.