Finds a specified prj file in the ArcGIS Coordinate Systems directory.

find-prj-file.py

import os, fnmatch, arcpy

def locate(pattern, root=arcpy.GetInstallInfo()["InstallDir"] + "\Coordinate Systems"):
    """Locate all files matching supplied filename pattern in and below
       supplied root directory.
    
    """
    for path, dirs, files in os.walk(os.path.abspath(root)):
        for filename in fnmatch.filter(files, pattern):
            yield os.path.join(path, filename)

prj = "Asia_Lambert_Conformal_Conic"

for f in locate(prj.replace("_", " ") + ".prj"):
    try:
        file_object = open(f, "r")
        all_text = file_object.read()
        print all_text[:6]
    finally:
        file_object.close()