diff --git a/reactos/base/setup/usetup/usetup.h b/reactos/base/setup/usetup/usetup.h
index 893e520b21b..2dfb99ba469 100644
--- a/reactos/base/setup/usetup/usetup.h
+++ b/reactos/base/setup/usetup/usetup.h
@@ -24,6 +24,9 @@
  * PROGRAMMER:      Eric Kohl
  */
 
+#ifndef _USETUP_PCH_
+#define _USETUP_PCH_
+
 /* C Headers */
 #include <stdio.h>
 #include <stdlib.h>
@@ -172,4 +175,4 @@ typedef enum _PAGE_NUMBER
   InsertTailList(current, &((NewEntry)->ListEntryField));\
 }
 
-/* EOF */
+#endif /* _USETUP_PCH_ */
diff --git a/reactos/base/shell/explorer/precomp.h b/reactos/base/shell/explorer/precomp.h
index cb8b740431b..831e8f92141 100644
--- a/reactos/base/shell/explorer/precomp.h
+++ b/reactos/base/shell/explorer/precomp.h
@@ -16,6 +16,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifndef _EXPLORER_H
+#define _EXPLORER_H
 
  //
  // Explorer clone - precompiled header support
@@ -51,3 +53,5 @@
 #include "externals.h"
 
 #include "resource.h"
+
+#endif /* _EXPLORER_H */
diff --git a/reactos/base/system/services/services.h b/reactos/base/system/services/services.h
index 01a04c4005f..2eac8178db6 100644
--- a/reactos/base/system/services/services.h
+++ b/reactos/base/system/services/services.h
@@ -2,6 +2,9 @@
  * services.h
  */
 
+#ifndef _SERVICES_H
+#define _SERVICES_H
+
 #include <stdio.h>
 
 #define WIN32_NO_STATUS
@@ -192,4 +195,4 @@ VOID ScmLogError(DWORD dwEventId,
                  LPCWSTR *lpStrings);
 VOID ScmWaitForLsa(VOID);
 
-/* EOF */
+#endif /* _SERVICES_H */