diff --git a/xpcom/ds/nsObserverService.cpp b/xpcom/ds/nsObserverService.cpp
index 1cf8ec96ea18..78d6a32e7dde 100644
--- a/xpcom/ds/nsObserverService.cpp
+++ b/xpcom/ds/nsObserverService.cpp
@@ -102,9 +102,7 @@ nsObserverService::Create(nsISupports* outer, const nsIID& aIID, void* *aInstanc
 
     nsRefPtr<nsObserverService> os = new nsObserverService();
 
-    // The cast is required for MSVC6, otherwise it complains about calling
-    // a private function.
-    if (!os || !((nsObserverService*) os)->mObserverTopicTable.IsInitialized())
+    if (!os || !os->mObserverTopicTable.IsInitialized())
         return NS_ERROR_OUT_OF_MEMORY;
 
     return os->QueryInterface(aIID, aInstancePtr);
diff --git a/xpcom/ds/nsWindowsRegKey.cpp b/xpcom/ds/nsWindowsRegKey.cpp
index 28a1482433f7..7f406505a0ff 100644
--- a/xpcom/ds/nsWindowsRegKey.cpp
+++ b/xpcom/ds/nsWindowsRegKey.cpp
@@ -43,12 +43,6 @@
 #include "nsString.h"
 #include "nsCOMPtr.h"
 
-// The Platform SDK included with VC6 does not define REG_QWORD.  VC 7's
-// WinNT.h defines REG_QWORD as follows:
-#ifndef REG_QWORD
-# define REG_QWORD 11
-#endif
-
 //-----------------------------------------------------------------------------
 
 // According to MSDN, the following limits apply (in characters excluding room