Updates removed many applications

[Charlie Kravetz]

RELEASE: Natty Narwhal 64bit Xubuntu
CD/DVD VARIANT: Installed months ago

SYMPTOMS:
Ran "sudo apt-get update" and then "sudo apt-get dist-upgrade". Many applications have been removed. Trying to reinstall results in:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 <PACKAGE> : Depends: python-??? but it is not going to be installed
E: Broken packages

running "aptitude why-not <PACKAGE>" results in :

Unable to find a reason to remove <PACKAGE>.

STEPS TO REPRODUCE:

1. sudo apt-get update
2. sudo apt-get dist-upgrade

restart