it works!! thanks!
but it is only possible to open .blend exes? and no 2d flashanims in a new screen or something?
u can’t open anything other than blend files or exes
You can open any file from python 
You have to import the os module, which isn’t included with blender, but is included with python. In the case of an exe you distribute, you can provide a local set of the required python modules and should be able to import the ones you need such as os.
The os.exec* functions let you ask the os to start an external file. They are described here: http://www.python.org/doc/current/lib/os-process.html