Steam blocking other software installation

I've tried to unninstall Steam by typing sudo apt-get purge steam and also remove steam. When I apt-get update, I get an error in the Steam repo:

Err http://repo.steampowered.com precise/steam amd64 Packages

and also

Err http://repo.steampowered.com precise/steam i386 Packages

Anytime I try to install another software, I can't. Does anyone knows how can I fix this?