diff --git a/src/dosinst.h b/src/dosinst.h
index b33426a..444af45 100644
--- a/src/dosinst.h
+++ b/src/dosinst.h
@@ -89,6 +89,7 @@
  */
 # ifndef KEY_WOW64_64KEY
 #  define KEY_WOW64_64KEY 0x0100
+#  define RegDeleteKeyEx(a, b, c, d) RegDeleteKey(a, b)
 # endif
 
 #define VIM_STARTMENU "Programs\\Vim " VIM_VERSION_SHORT