diff --git a/reactos/dll/directx/ddraw/Ddraw/ddraw_main.c b/reactos/dll/directx/ddraw/Ddraw/ddraw_main.c
index b9b09bada08..2a7a6051c8c 100644
--- a/reactos/dll/directx/ddraw/Ddraw/ddraw_main.c
+++ b/reactos/dll/directx/ddraw/Ddraw/ddraw_main.c
@@ -152,13 +152,19 @@ Main_DirectDraw_GetFourCCCodes(LPDIRECTDRAW7 iface, LPDWORD lpNumCodes, LPDWORD
     EnterCriticalSection(&ddcs);
 
    if(!lpNumCodes)
+   {
+      LeaveCriticalSection(&ddcs);
       return DDERR_INVALIDPARAMS;
+   }
 
    if(lpCodes)
-      memcpy(lpCodes, This->lpLcl->lpGbl->lpdwFourCC, sizeof(DWORD)*(*lpNumCodes));
-   else 
+   {
+      memcpy(lpCodes, This->lpLcl->lpGbl->lpdwFourCC, sizeof(DWORD)* MIN(This->lpLcl->lpGbl->dwNumFourCC, *lpNumCodes));
+   }
+   else
+   {
       *lpNumCodes = This->lpLcl->lpGbl->dwNumFourCC;
-
+   }
 
     LeaveCriticalSection(&ddcs);
     return DD_OK;
diff --git a/reactos/dll/directx/ddraw/Ddraw/ddraw_setcooperativelevel.c b/reactos/dll/directx/ddraw/Ddraw/ddraw_setcooperativelevel.c
index be767b449d0..43808d2ea9d 100644
--- a/reactos/dll/directx/ddraw/Ddraw/ddraw_setcooperativelevel.c
+++ b/reactos/dll/directx/ddraw/Ddraw/ddraw_setcooperativelevel.c
@@ -33,6 +33,9 @@ Main_DirectDraw_SetCooperativeLevel (LPDIRECTDRAW7 iface, HWND hwnd, DWORD coopl
     }
 #endif
 
+	if(hwnd && IsWindow(hwnd))
+		return DDERR_INVALIDPARAMS;
+
     /* Tests suggest that we need one of them: */
     if(!(cooplevel & (DDSCL_SETFOCUSWINDOW |
                       DDSCL_NORMAL         |