diff --git a/reactos/include/ddk/ntdddisk.h b/reactos/include/ddk/ntdddisk.h
index db3b1eba2bd..707abb268b5 100644
--- a/reactos/include/ddk/ntdddisk.h
+++ b/reactos/include/ddk/ntdddisk.h
@@ -315,9 +315,9 @@ typedef struct _DISK_GEOMETRY_EX {
 typedef struct _PARTITION_INFORMATION {
   LARGE_INTEGER  StartingOffset;
   LARGE_INTEGER  PartitionLength;
-  DWORD  HiddenSectors;
-  DWORD  PartitionNumber;
-  BYTE  PartitionType;
+  ULONG  HiddenSectors;
+  ULONG  PartitionNumber;
+  UCHAR  PartitionType;
   BOOLEAN  BootIndicator;
   BOOLEAN  RecognizedPartition;
   BOOLEAN  RewritePartition;
@@ -429,9 +429,9 @@ typedef struct _GET_LENGTH_INFORMATION {
 } GET_LENGTH_INFORMATION, *PGET_LENGTH_INFORMATION;
 
 typedef struct _REASSIGN_BLOCKS {
-  WORD  Reserved;
-  WORD  Count;
-  DWORD  BlockNumber[1];
+  USHORT  Reserved;
+  USHORT  Count;
+  ULONG  BlockNumber[1];
 } REASSIGN_BLOCKS, *PREASSIGN_BLOCKS;
 
 typedef struct _SET_PARTITION_INFORMATION {
@@ -451,7 +451,7 @@ typedef struct _SET_PARTITION_INFORMATION_EX {
 
 typedef struct _VERIFY_INFORMATION {
   LARGE_INTEGER  StartingOffset;
-  DWORD  Length;
+  ULONG  Length;
 } VERIFY_INFORMATION, *PVERIFY_INFORMATION;
 
 typedef enum {
diff --git a/reactos/include/ddk/ntstatus.h b/reactos/include/ddk/ntstatus.h
index 1e8a65e31af..5f87e376aad 100644
--- a/reactos/include/ddk/ntstatus.h
+++ b/reactos/include/ddk/ntstatus.h
@@ -20,8 +20,8 @@
  *
  */
 
-#ifndef _NTSTATUS_H
-#define _NTSTATUS_H
+#ifndef _NTSTATUS_
+#define _NTSTATUS_
 
 #if __GNUC__ >=3
 #pragma GCC system_header
diff --git a/reactos/include/ddk/tdiinfo.h b/reactos/include/ddk/tdiinfo.h
index 65731ef9d88..4d686cc61f2 100644
--- a/reactos/include/ddk/tdiinfo.h
+++ b/reactos/include/ddk/tdiinfo.h
@@ -97,8 +97,8 @@ typedef struct _TCP_REQUEST_QUERY_INFORMATION_EX32 {
 
 typedef struct _TCP_REQUEST_SET_INFORMATION_EX {
   TDIObjectID  ID;
-  UINT  BufferSize;
-  UCHAR  Buffer[1];
+  unsigned int BufferSize;
+  unsigned char Buffer[1];
 } TCP_REQUEST_SET_INFORMATION_EX, *PTCP_REQUEST_SET_INFORMATION_EX;
 
 #ifdef __cplusplus
diff --git a/reactos/include/ddk/tvout.h b/reactos/include/ddk/tvout.h
index 9451b62c4fa..d174bc3349e 100644
--- a/reactos/include/ddk/tvout.h
+++ b/reactos/include/ddk/tvout.h
@@ -89,28 +89,28 @@
 
 typedef struct _VIDEOPARAMETERS {
   GUID  Guid;
-  DWORD  dwOffset;
-  DWORD  dwCommand;
-  DWORD  dwFlags;
-  DWORD  dwMode;
-  DWORD  dwTVStandard;
-  DWORD  dwAvailableModes;
-  DWORD  dwAvailableTVStandard;
-  DWORD  dwFlickerFilter;
-  DWORD  dwOverScanX;
-  DWORD  dwOverScanY;
-  DWORD  dwMaxUnscaledX;
-  DWORD  dwMaxUnscaledY;
-  DWORD  dwPositionX;
-  DWORD  dwPositionY;
-  DWORD  dwBrightness;
-  DWORD  dwContrast;
-  DWORD  dwCPType;
-  DWORD  dwCPCommand;
-  DWORD  dwCPStandard;
-  DWORD  dwCPKey;
-  BYTE  bCP_APSTriggerBits;
-  BYTE  bOEMCopyProtection[256];
+  ULONG  dwOffset;
+  ULONG  dwCommand;
+  ULONG  dwFlags;
+  ULONG  dwMode;
+  ULONG  dwTVStandard;
+  ULONG  dwAvailableModes;
+  ULONG  dwAvailableTVStandard;
+  ULONG  dwFlickerFilter;
+  ULONG  dwOverScanX;
+  ULONG  dwOverScanY;
+  ULONG  dwMaxUnscaledX;
+  ULONG  dwMaxUnscaledY;
+  ULONG  dwPositionX;
+  ULONG  dwPositionY;
+  ULONG  dwBrightness;
+  ULONG  dwContrast;
+  ULONG  dwCPType;
+  ULONG  dwCPCommand;
+  ULONG  dwCPStandard;
+  ULONG  dwCPKey;
+  ULONG  bCP_APSTriggerBits;
+  UCHAR  bOEMCopyProtection[256];
 } VIDEOPARAMETERS, *PVIDEOPARAMETERS, FAR *LPVIDEOPARAMETERS;
 
 
diff --git a/reactos/include/ddk/video.h b/reactos/include/ddk/video.h
index bfb1e24c383..9ce8e93bb78 100644
--- a/reactos/include/ddk/video.h
+++ b/reactos/include/ddk/video.h
@@ -86,6 +86,10 @@ typedef HW_DMA_RETURN
     PDMA  pDma);
 
 
+#ifdef PAGED_CODE
+#undef PAGED_CODE
+#endif
+
 #ifdef DBG
 
 #define PAGED_CODE() \
diff --git a/reactos/include/ddk/winddi.h b/reactos/include/ddk/winddi.h
index c3f25e529e3..e83e74e982f 100644
--- a/reactos/include/ddk/winddi.h
+++ b/reactos/include/ddk/winddi.h
@@ -314,11 +314,11 @@ typedef struct _DEVINFO {
   FLONG  flGraphicsCaps2;
 } DEVINFO, *PDEVINFO;
 
-typedef struct _DRIVEROBJ *PDRIVEROBJ;
+struct _DRIVEROBJ;
 
 typedef BOOL
 (APIENTRY CALLBACK *FREEOBJPROC)(
-  IN PDRIVEROBJ  pDriverObj);
+  IN struct _DRIVEROBJ  *pDriverObj);
 
 typedef struct _DRIVEROBJ {
   PVOID  pvObj;
@@ -1110,6 +1110,17 @@ typedef struct _XLATEOBJ {
   ULONG  *pulXlate;
 } XLATEOBJ;
 
+/* WNDOBJCHANGEPROC.fl constants */
+#define WOC_RGN_CLIENT_DELTA              0x00000001
+#define WOC_RGN_CLIENT                    0x00000002
+#define WOC_RGN_SURFACE_DELTA             0x00000004
+#define WOC_RGN_SURFACE                   0x00000008
+#define WOC_CHANGED                       0x00000010
+#define WOC_DELETE                        0x00000020
+#define WOC_DRAWN                         0x00000040
+#define WOC_SPRITE_OVERLAP                0x00000080
+#define WOC_SPRITE_NO_OVERLAP             0x00000100
+
 typedef VOID (APIENTRY CALLBACK *WNDOBJCHANGEPROC)(
   IN WNDOBJ  *pwo,
   IN FLONG  fl);
@@ -3526,23 +3537,6 @@ APIENTRY
 DrvUnloadFontFile(
   IN ULONG_PTR  iFile);
 
-/* WNDOBJCHANGEPROC.fl constants */
-#define WOC_RGN_CLIENT_DELTA              0x00000001
-#define WOC_RGN_CLIENT                    0x00000002
-#define WOC_RGN_SURFACE_DELTA             0x00000004
-#define WOC_RGN_SURFACE                   0x00000008
-#define WOC_CHANGED                       0x00000010
-#define WOC_DELETE                        0x00000020
-#define WOC_DRAWN                         0x00000040
-#define WOC_SPRITE_OVERLAP                0x00000080
-#define WOC_SPRITE_NO_OVERLAP             0x00000100
-
-typedef VOID
-(APIENTRY CALLBACK * WNDOBJCHANGEPROC)(
-  WNDOBJ  *pwo,
-  FLONG  fl);
-
-
 typedef BOOL
 (APIENTRY *PFN_DrvAlphaBlend)(
   IN SURFOBJ  *psoDest,
diff --git a/reactos/include/psdk/ntstatus.h b/reactos/include/psdk/ntstatus.h
index 13c445ceb71..3a4811d44e8 100644
--- a/reactos/include/psdk/ntstatus.h
+++ b/reactos/include/psdk/ntstatus.h
@@ -47,10 +47,10 @@
  */
 
 #define STATUS_SUCCESS                   ((NTSTATUS)0x00000000)
-#define STATUS_SEVERITY_SUCCESS          ((NTSTATUS)0x00000000)
-#define STATUS_SEVERITY_INFORMATIONAL    ((NTSTATUS)0x00000001)
-#define STATUS_SEVERITY_WARNING          ((NTSTATUS)0x00000002)
-#define STATUS_SEVERITY_ERROR            ((NTSTATUS)0x00000003)
+#define STATUS_SEVERITY_SUCCESS          0x0
+#define STATUS_SEVERITY_INFORMATIONAL    0x1
+#define STATUS_SEVERITY_WARNING          0x2
+#define STATUS_SEVERITY_ERROR            0x3
 
 #define STATUS_WAIT_1                    ((NTSTATUS)0x00000001)
 #define STATUS_WAIT_2                    ((NTSTATUS)0x00000002)