diff --git a/trunk/desmume/src/GPU.c b/trunk/desmume/src/GPU.c
index d9a8ecda0..03a644bee 100644
--- a/trunk/desmume/src/GPU.c
+++ b/trunk/desmume/src/GPU.c
@@ -128,7 +128,7 @@ void GPU_DeInit(GPU * gpu)
 void GPU_setVideoProp(GPU * gpu, u32 p)
 {
         BOOL LayersEnable[5];
-        u16 WinBG;
+        u16 WinBG=0;
 	struct _DISPCNT * cnt = &gpu->dispCnt.bitfield;
 
 	gpu->dispCnt.integer = p;
@@ -185,8 +185,11 @@ void GPU_setVideoProp(GPU * gpu, u32 p)
 	GPU_setBGProp(gpu, 1, T1ReadWord(ARM9Mem.ARM9_REG, gpu->core * ADDRESS_STEP_4KB + 10));
 	GPU_setBGProp(gpu, 0, T1ReadWord(ARM9Mem.ARM9_REG, gpu->core * ADDRESS_STEP_4KB + 8));
 	
+	if (cnt->Win0_Enable || cnt->Win1_Enable)
+	{
         WinBG = (gpu->WINDOW_INCNT.val | gpu->WINDOW_OUTCNT.val);
         WinBG = WinBG | (WinBG >> 8);
+	}
 
 	// Let's prepare the field for WINDOWS implementation
 	LayersEnable[0] = gpu->dispBG[0] && (cnt->BG0_Enable || (WinBG & 0x1));