diff --git a/reactos/include/win32k/ntuser.h b/reactos/include/win32k/ntuser.h
index 55843095b2e..a772ce0f54f 100644
--- a/reactos/include/win32k/ntuser.h
+++ b/reactos/include/win32k/ntuser.h
@@ -1714,12 +1714,12 @@ STDCALL
 NtUserUnlockWindowStation(
   HWINSTA hWindowStation);
 
-DWORD
+BOOL
 STDCALL
 NtUserUnregisterClass(
-  DWORD Unknown0,
-  DWORD Unknown1,
-  DWORD Unknown2);
+  LPCWSTR ClassNameOrAtom,
+  HINSTANCE hInstance,
+  DWORD Unknown);
 
 BOOL
 STDCALL
diff --git a/reactos/lib/user32/windows/class.c b/reactos/lib/user32/windows/class.c
index 50cf2bfabde..9f5f7eb0967 100644
--- a/reactos/lib/user32/windows/class.c
+++ b/reactos/lib/user32/windows/class.c
@@ -1,4 +1,4 @@
-/* $Id: class.c,v 1.40 2003/12/07 10:31:21 navaraf Exp $
+/* $Id: class.c,v 1.41 2003/12/07 22:25:34 weiden Exp $
  *
  * COPYRIGHT:       See COPYING in the top level directory
  * PROJECT:         ReactOS user32.dll
@@ -731,7 +731,7 @@ SetWindowLongW(
 
 
 /*
- * @unimplemented
+ * @implemented
  */
 WINBOOL
 STDCALL
@@ -739,13 +739,33 @@ UnregisterClassA(
   LPCSTR lpClassName,
   HINSTANCE hInstance)
 {
-  UNIMPLEMENTED;
-  return FALSE;
+  LPWSTR ClassName;
+  NTSTATUS Status;
+  WINBOOL Result;
+  
+  if(!IS_ATOM(lpClassName))
+  {
+    Status = HEAP_strdupAtoW(&ClassName, lpClassName, NULL);
+    if(!NT_SUCCESS(Status))
+    {
+      SetLastError(RtlNtStatusToDosError(Status));
+      return FALSE;
+    }
+  }
+  else
+    ClassName = (LPWSTR)lpClassName;
+  
+  Result = (WINBOOL)NtUserUnregisterClass((LPCWSTR)ClassName, hInstance, 0);
+  
+  if(ClassName && !IS_ATOM(lpClassName)) 
+    HEAP_free(ClassName);
+  
+  return Result;
 }
 
 
 /*
- * @unimplemented
+ * @implemented
  */
 WINBOOL
 STDCALL
@@ -753,8 +773,7 @@ UnregisterClassW(
   LPCWSTR lpClassName,
   HINSTANCE hInstance)
 {
-  UNIMPLEMENTED;
-  return FALSE;
+  return (WINBOOL)NtUserUnregisterClass(lpClassName, hInstance, 0);
 }
 
 /* EOF */
diff --git a/reactos/subsys/win32k/ntuser/class.c b/reactos/subsys/win32k/ntuser/class.c
index ac64540181d..dd1266441d2 100644
--- a/reactos/subsys/win32k/ntuser/class.c
+++ b/reactos/subsys/win32k/ntuser/class.c
@@ -16,7 +16,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
-/* $Id: class.c,v 1.42 2003/12/07 10:31:21 navaraf Exp $
+/* $Id: class.c,v 1.43 2003/12/07 22:25:34 weiden Exp $
  *
  * COPYRIGHT:        See COPYING in the top level directory
  * PROJECT:          ReactOS kernel
@@ -157,6 +157,7 @@ NtUserGetClassInfo(HINSTANCE hInstance, LPCWSTR lpClassName,
 {
    PWNDCLASS_OBJECT Class;
    NTSTATUS Status;
+   RTL_ATOM Atom;
 
    Status = ClassReferenceClassByNameOrAtom(&Class, lpClassName);
    if (!NT_SUCCESS(Status))
@@ -187,8 +188,11 @@ NtUserGetClassInfo(HINSTANCE hInstance, LPCWSTR lpClassName,
       lpWndClassEx->lpszMenuName = (LPCWSTR)NULL;
    lpWndClassEx->lpszClassName = lpClassName;
    lpWndClassEx->hIconSm = Class->hIconSm;
+   Atom = Class->Atom;
+   
+   ObmDereferenceObject(Class);
 
-   return Class->Atom;
+   return Atom;
 }
 
 ULONG FASTCALL
@@ -288,7 +292,7 @@ IntCreateClass(CONST WNDCLASSEXW *lpwcx,
 	{          
 		return(NULL);
 	}
-
+	
 	ClassObject->cbSize = lpwcx->cbSize;
 	ClassObject->style = lpwcx->style;
 	ClassObject->cbClsExtra = lpwcx->cbClsExtra;
@@ -606,13 +610,45 @@ NtUserSetClassWord(DWORD Unknown0,
   return(0);
 }
 
-DWORD STDCALL
-NtUserUnregisterClass(DWORD Unknown0,
-		      DWORD Unknown1,
-		      DWORD Unknown2)
+BOOL STDCALL
+NtUserUnregisterClass(LPCWSTR ClassNameOrAtom,
+		      HINSTANCE hInstance,
+		      DWORD Unknown)
 {
-  UNIMPLEMENTED;
-  return(0);
+  NTSTATUS Status;
+  PWNDCLASS_OBJECT Class;
+  
+  if(!ClassNameOrAtom)
+  {
+    SetLastWin32Error(ERROR_INVALID_PARAMETER);
+    return FALSE;
+  }
+  
+  Status = ClassReferenceClassByNameOrAtom(&Class, ClassNameOrAtom);
+  if(!NT_SUCCESS(Status))
+  {
+    SetLastWin32Error(ERROR_CLASS_DOES_NOT_EXIST);
+    return FALSE;
+  }
+  
+  if(ObmGetReferenceCount(Class) > 2)
+  {
+    ObmDereferenceObject(Class);
+    SetLastWin32Error(ERROR_CLASS_HAS_WINDOWS);
+    return FALSE;
+  }
+  
+  /* Dereference the ClassReferenceClassByNameOrAtom() call */
+  ObmDereferenceObject(Class);
+  
+  RemoveEntryList(&Class->ListEntry);
+  
+  /* FIXME - delete the atom? */
+  
+  /* Free the object */
+  ObmDereferenceObject(Class);
+  
+  return TRUE;
 }
 
 /* EOF */
diff --git a/reactos/subsys/win32k/ntuser/window.c b/reactos/subsys/win32k/ntuser/window.c
index 38ab3f8ff8d..296a832b7c1 100644
--- a/reactos/subsys/win32k/ntuser/window.c
+++ b/reactos/subsys/win32k/ntuser/window.c
@@ -16,7 +16,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
-/* $Id: window.c,v 1.152 2003/12/07 19:29:33 weiden Exp $
+/* $Id: window.c,v 1.153 2003/12/07 22:25:34 weiden Exp $
  *
  * COPYRIGHT:        See COPYING in the top level directory
  * PROJECT:          ReactOS kernel
@@ -368,7 +368,8 @@ static LRESULT IntDestroyWindow(PWINDOW_OBJECT Window,
   
   IntDestroyScrollBar(Window, SB_VERT);
   IntDestroyScrollBar(Window, SB_HORZ);
-
+  
+  ObmDereferenceObject(Window->Class);
   Window->Class = NULL;
   ObmCloseHandle(ProcessData->WindowStation->HandleTable, Window->Self);
 
@@ -558,7 +559,12 @@ IntCreateDesktopWindow(PWINSTATION_OBJECT WindowStation,
   PWSTR WindowName;
   HWND Handle;
   PWINDOW_OBJECT WindowObject;
-
+  
+  if(!DesktopClass)
+  {
+    return (HWND)0;
+  }
+  
   /* Create the window object. */
   WindowObject = (PWINDOW_OBJECT)ObmCreateObject(WindowStation->HandleTable, 
 						 &Handle, 
@@ -572,6 +578,7 @@ IntCreateDesktopWindow(PWINSTATION_OBJECT WindowStation,
   /*
    * Fill out the structure describing it.
    */
+  ObmReferenceObject(DesktopClass);
   WindowObject->Class = DesktopClass;
   WindowObject->ExStyle = 0;
   WindowObject->Style = WS_VISIBLE;