I own Skyrim, now suddenly it won't load and tells me the game is not able to be played in family view. I have disabled family view in Steam, restarted but still no joy.
There must be a problem with the Steam configuration files linked to your profile. Your best bet is to reinstall Steam.
Beforehand, store the games currently in your Steam library folder (by default 'C:\Program Files\steamapps\common') in a different location, and move them back after reinstallation in order to keep them. Afterwards, you might have to use the 'Install' option in Steam for the games you moved to be found again.