diff --git a/Makefile.frag.w32 b/Makefile.frag.w32
index 9942ddc..bab7d26 100644
--- a/Makefile.frag.w32
+++ b/Makefile.frag.w32
@@ -1,6 +1,5 @@
 
 CMAKE=cmake.exe
-COMPOSER_PHAR=C:\ProgramData\ComposerSetup\bin\composer.phar
 PHP_BINARY=$(PHP_PREFIX)\php.exe
 
 CMAKE_CONFIGURE = $(CMAKE) -DCMAKE_INSTALL_PREFIX=$(AWSCRT_DIR)\build\install -DCMAKE_PREFIX_PATH=$(AWSCRT_DIR)\build\install -DBUILD_TESTING=OFF -DCMAKE_BUILD_TYPE=$(CMAKE_BUILD_TYPE)
@@ -31,5 +30,6 @@ $(AWSCRT_DIR)\ext\api.h : $(AWSCRT_DIR)\src\api.h
 
 # Use PHPUnit and composer to run tests
 test-awscrt: install $(AWSCRT_DIR)\src\api.h $(BUILD_DIR)\php_awscrt.dll
-	$(PHP_BINARY) -c $(AWSCRT_DIR)\php-win.ini c:\tools\php\composer.phar --working-dir=$(AWSCRT_DIR) update
-	$(PHP_BINARY) -c $(AWSCRT_DIR)\php-win.ini c:\tools\php\composer.phar --working-dir=$(AWSCRT_DIR) run test-win
\ No newline at end of file
+	COMPOSER_PHAR = where.exe composer.phar
+	$(PHP_BINARY) -c $(AWSCRT_DIR)\php-win.ini ${COMPOSER_PHAR} --working-dir=$(AWSCRT_DIR) update
+	$(PHP_BINARY) -c $(AWSCRT_DIR)\php-win.ini ${COMPOSER_PHAR} --working-dir=$(AWSCRT_DIR) run test-win
\ No newline at end of file