Here's my next brainstorm, now that I understand it's a hung apt install. This may work if the entire aptitude system isn't locked. Make sure no other synaptic is running.
First, trying the usual options:
Code:
sudo killall aptitude
sudo killall synaptic
sudo aptitude purge appname && sudo aptitude remove appname && sudo aptitude clean && sudo aptitude autoclean
When that doesn't work 
Generate a list of installed packages and see if you can find the one you attempted to install:
Code:
sudo dpkg --get-selections >~/Desktop/bad-install
gedit ~/Desktop/bad-install
If you find the troublemaker, check the status. Either change it to 'deinstall' or remove it completely. Then run:
Code:
sudo dpkg --clear-selections
sudo dpkg --set-selections <~/Desktop/bad-install
sudo apt-get -u dselect-upgrade
Maybe that will clear it. If nothing else, it bumps your thread. Good luck.
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