Each time that the Workspace is saved a copy is archived to a zip file located in My Workspace/Backup. Within Artist you can select Main Menu/File/Restore Workspace. This will display a list od workspace file names and dates. The saves are at the bottom of the list. Restore to before the last save scroll to the bottom of the list, select the date and click Restore.
From outside of Artist, select Start/All Programs/ShowCAD Artist 3/Restore Workspace. This will ask you to select a zip file. When you open the file you will get the archive list. This is useful if the workspace has become corrupt and is preventing Artist from launching.