1) Create a batch file "runargo.bat" in your ArgoUML directory which looks something like this: @echo off cd "C:\ArgoUML" start javaw -cp "argouml.jar" org.argouml.application.Main %1 /B replacing "C:\ArgoUML" as appropriate.

2) Associate your .zargo files with this batch file (just double-click a .zargo file and follow the instructions).