diff --git a/reactos/include/ddk/iotypes.h b/reactos/include/ddk/iotypes.h
index 6a83dd11bd7..7f919780979 100644
--- a/reactos/include/ddk/iotypes.h
+++ b/reactos/include/ddk/iotypes.h
@@ -1196,18 +1196,18 @@ typedef struct _SCATTER_GATHER_LIST {
   SCATTER_GATHER_ELEMENT Elements[1];
 } SCATTER_GATHER_LIST, *PSCATTER_GATHER_LIST;
 
-typedef VOID STDCALL (*PPUT_DMA_ADAPTER)(
+typedef VOID (STDCALL *PPUT_DMA_ADAPTER)(
   PDMA_ADAPTER DmaAdapter
   );
 
-typedef PVOID STDCALL (*PALLOCATE_COMMON_BUFFER)(
+typedef PVOID (STDCALL *PALLOCATE_COMMON_BUFFER)(
   IN PDMA_ADAPTER DmaAdapter,
   IN ULONG Length,
   OUT PPHYSICAL_ADDRESS LogicalAddress,
   IN BOOLEAN CacheEnabled
   );
 
-typedef VOID STDCALL (*PFREE_COMMON_BUFFER)(
+typedef VOID (STDCALL *PFREE_COMMON_BUFFER)(
   IN PDMA_ADAPTER DmaAdapter,
   IN ULONG Length,
   IN PHYSICAL_ADDRESS LogicalAddress,
@@ -1215,7 +1215,7 @@ typedef VOID STDCALL (*PFREE_COMMON_BUFFER)(
   IN BOOLEAN CacheEnabled
   );
 
-typedef NTSTATUS STDCALL (*PALLOCATE_ADAPTER_CHANNEL)(
+typedef NTSTATUS (STDCALL *PALLOCATE_ADAPTER_CHANNEL)(
   IN PDMA_ADAPTER DmaAdapter,
   IN PDEVICE_OBJECT DeviceObject,
   IN ULONG NumberOfMapRegisters,
@@ -1223,7 +1223,7 @@ typedef NTSTATUS STDCALL (*PALLOCATE_ADAPTER_CHANNEL)(
   IN PVOID Context
   );
 
-typedef BOOLEAN STDCALL (*PFLUSH_ADAPTER_BUFFERS)(
+typedef BOOLEAN (STDCALL *PFLUSH_ADAPTER_BUFFERS)(
   IN PDMA_ADAPTER DmaAdapter,
   IN PMDL Mdl,
   IN PVOID MapRegisterBase,
@@ -1232,17 +1232,17 @@ typedef BOOLEAN STDCALL (*PFLUSH_ADAPTER_BUFFERS)(
   IN BOOLEAN WriteToDevice
   );
 
-typedef VOID STDCALL (*PFREE_ADAPTER_CHANNEL)(
+typedef VOID (STDCALL *PFREE_ADAPTER_CHANNEL)(
   IN PDMA_ADAPTER DmaAdapter
   );
 
-typedef VOID STDCALL (*PFREE_MAP_REGISTERS)(
+typedef VOID (STDCALL *PFREE_MAP_REGISTERS)(
   IN PDMA_ADAPTER DmaAdapter,
   PVOID MapRegisterBase,
   ULONG NumberOfMapRegisters
   );
 
-typedef PHYSICAL_ADDRESS STDCALL (*PMAP_TRANSFER)(
+typedef PHYSICAL_ADDRESS (STDCALL *PMAP_TRANSFER)(
   IN PDMA_ADAPTER DmaAdapter,
   IN PMDL Mdl,
   IN PVOID MapRegisterBase,
@@ -1251,22 +1251,22 @@ typedef PHYSICAL_ADDRESS STDCALL (*PMAP_TRANSFER)(
   IN BOOLEAN WriteToDevice
   );
 
-typedef ULONG STDCALL (*PGET_DMA_ALIGNMENT)(
+typedef ULONG (STDCALL *PGET_DMA_ALIGNMENT)(
   IN PDMA_ADAPTER DmaAdapter
   );
 
-typedef ULONG STDCALL (*PREAD_DMA_COUNTER)(
+typedef ULONG (STDCALL *PREAD_DMA_COUNTER)(
   IN PDMA_ADAPTER DmaAdapter
   );
 
-typedef VOID STDCALL (*PDRIVER_LIST_CONTROL)(
+typedef VOID (STDCALL *PDRIVER_LIST_CONTROL)(
   IN struct _DEVICE_OBJECT *DeviceObject,
   IN struct _IRP *Irp,
   IN PSCATTER_GATHER_LIST ScatterGather,
   IN PVOID Context
   );
 
-typedef NTSTATUS STDCALL (*PGET_SCATTER_GATHER_LIST)(
+typedef NTSTATUS (STDCALL *PGET_SCATTER_GATHER_LIST)(
   IN PDMA_ADAPTER DmaAdapter,
   IN PDEVICE_OBJECT DeviceObject,
   IN PMDL Mdl,
@@ -1277,7 +1277,7 @@ typedef NTSTATUS STDCALL (*PGET_SCATTER_GATHER_LIST)(
   IN BOOLEAN WriteToDevice
   );
 
-typedef VOID STDCALL (*PPUT_SCATTER_GATHER_LIST)(
+typedef VOID (STDCALL *PPUT_SCATTER_GATHER_LIST)(
   IN PDMA_ADAPTER DmaAdapter,
   IN PSCATTER_GATHER_LIST ScatterGather,
   IN BOOLEAN WriteToDevice
diff --git a/reactos/ntoskrnl/io/deviface.c b/reactos/ntoskrnl/io/deviface.c
index b1cc886cf64..4d42858241a 100644
--- a/reactos/ntoskrnl/io/deviface.c
+++ b/reactos/ntoskrnl/io/deviface.c
@@ -12,13 +12,13 @@
 /* INCLUDES ******************************************************************/
 
 #include <ntoskrnl.h>
-#include <ole32/guiddef.h>
-#ifdef DEFINE_GUID
-DEFINE_GUID(GUID_SERENUM_BUS_ENUMERATOR, 0x4D36E978L, 0xE325, 0x11CE, 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18);
-#endif
+
 #define NDEBUG
 #include <internal/debug.h>
 
+DEFINE_GUID(GUID_SERENUM_BUS_ENUMERATOR, 
+            0x4D36E978L, 0xE325, 0x11CE, 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18);
+
 /* FUNCTIONS *****************************************************************/
 
 /*
@@ -574,7 +574,7 @@ IoRegisterDeviceInterface(
    PWCHAR KeyNameString = L"\\Device\\Serenum";
 
    DPRINT("IoRegisterDeviceInterface called (UNIMPLEMENTED)\n");
-   if (IsEqualGUID(InterfaceClassGuid, (LPGUID)&GUID_SERENUM_BUS_ENUMERATOR))
+   if (!memcmp(InterfaceClassGuid, (LPGUID)&GUID_SERENUM_BUS_ENUMERATOR, sizeof(GUID)))
    {
       RtlInitUnicodeString(SymbolicLinkName, KeyNameString);
       return STATUS_SUCCESS;
diff --git a/reactos/ntoskrnl/io/pnpdma.c b/reactos/ntoskrnl/io/pnpdma.c
index 77fff2c5cb0..854b7fbf328 100644
--- a/reactos/ntoskrnl/io/pnpdma.c
+++ b/reactos/ntoskrnl/io/pnpdma.c
@@ -14,11 +14,6 @@
 #include <ntoskrnl.h>
 #define NDEBUG
 #include <internal/debug.h>
-#ifdef __USE_W32API
-#include <initguid.h>
-#else
-#include <ole32/guiddef.h>
-#endif
 #include <ddk/wdmguid.h>
 
 typedef struct _DMA_ADAPTER_INTERNAL {
diff --git a/reactos/ntoskrnl/io/pnpmgr.c b/reactos/ntoskrnl/io/pnpmgr.c
index 749534e2d0c..a5f20ad0515 100644
--- a/reactos/ntoskrnl/io/pnpmgr.c
+++ b/reactos/ntoskrnl/io/pnpmgr.c
@@ -1,4 +1,4 @@
-/* $Id: pnpmgr.c,v 1.52 2004/11/19 21:31:02 navaraf Exp $
+/* $Id$
  *
  * COPYRIGHT:      See COPYING in the top level directory
  * PROJECT:        ReactOS kernel
@@ -12,7 +12,6 @@
 /* INCLUDES ******************************************************************/
 
 #include <ntoskrnl.h>
-#include <ole32/guiddef.h>
 
 #define NDEBUG
 #include <internal/debug.h>