I installed Open Octave Studio and Midi 2012 according to the instructions from this PPA, but Midi does not recognize the jack and does not works, so I want to delete it and Studio. How can I delete it?
If you followed the PPA instructions you installed oomidi-2012 linuxsampler.
To uninstall with a terminal
To make apt-get remove any configuration files as well - use purge in place of remove.
If the install command installed other packages you might be left with those, autoremove will remove those.