Most installations of Aeris Calendar use the "Application Data" folder to store the settings. The location of this folder depends on the Windows version you're using:

• Windows 98/ME:
  C:\Windows\All Users\Application Data\Aeris Calendar\
• Windows 2000/XP:
  C:\Documents and Settings\{user}\Application Data\Aeris Calendar\
• Vista/Windows 7:
  C:\Users\{user}\AppData\Roaming\AerisCalendar\

Save the entire folder and restore it to the corresponding folder on the target computer.

If using a portable installation, it is recommended that you backup the entire installation folder, which will also contain the "Settings" subfolder.