The Windows build number for 2.3.3c1 is 50.
diff --git a/PCbuild/BUILDno.txt b/PCbuild/BUILDno.txt
index 473c80b..5c9af5b 100644
--- a/PCbuild/BUILDno.txt
+++ b/PCbuild/BUILDno.txt
@@ -33,6 +33,8 @@
 
 Windows Python BUILD numbers
 ----------------------------
+  50    2.3.3c1
+        5-Dec-2003
   49    2.3.2 (final)
         3-Oct-2003
   48    2.3.2c1