I used to have Astah installed. It was free, but not only professional is available. I replaced the computer and don't have the download.
Are they available from anywhere to download? I would like to work on the UML diagrams in that program, but I don't want to pay for the whole suite.
If it is not available in any old file download sites, are there other free apps that are comparable?
The Astah Community Edition download link is http://astah.net/download#community.
From the list of free UML tools the most comparable tool seems to be the Modelio.