Finding location of an executable in a windows machine?

[nonsense at mynonsense.net]

My python script calls another windows program file. I have the path
to that program hardcoded in it. Is there a way for python to
automatically find the path to this program?

testapp_path = "C:\\Program Files\\testapp\\version\\61\\"

Or do i have to do a brute force approach to searching all drives/
folders till it finds a path matching my program name?