Re: Can't login in to battlelog ERROR: "Buy BF3 to get access to Battlelog" ?

That's a weird message if you already own the game.  Try uninstalling the Battlefield Web Plugin from your Control Panel, clearing the cache in your browser and restarting your computer.  Once you go back to battlelog.battlefield.com it should redownload the Battlefield Web Plugin and allow you access.  If you're still getting that error message, look in Origin at your My Games tab and make certain you're still seeing that you have Battlefield 3 in your account and that it's installed correctly on your computer.  You may have to uninstall and reinstall the game.