C / C++ / MFC

I've created an application that paints on the window using GDI functions. It works fine. But because it is still under development it sometimes craches. It seems that if there are certain craches Windows Vista suddenly decides to treat my application in a new way: while drawing on the window it decides it must redraw that was on the screen when i started my application. The effect is that some drawing is lost. Windows continues with this behavour till i reboot my pc. After i booted the same piece of code draws the window correctly. I used Spy++ to find out what's happening. When the window is correctly displayed i see the following:

<00037> 00340626 P WM_LBUTTONDOWN fwKeys:MK_LBUTTON xPos:1215 yPos:640
<00038> 00340626 P WM_LBUTTONUP fwKeys:0000 xPos:1215 yPos:640
<00039> 00340626 P WM_LBUTTONDOWN fwKeys:MK_LBUTTON xPos:1249 yPos:711
<00040> 00340626 P WM_LBUTTONUP fwKeys:0000 xPos:1249 yPos:711

(I press the mousebutton to start drawing, it draws the window, i press the mousebutton again to close the window)

When things go wrong Spy++ reports the following:

<00037> 00340626 P WM_LBUTTONDOWN fwKeys:MK_LBUTTON xPos:1219 yPos:643
<00038> 00340626 P WM_LBUTTONUP fwKeys:0000 xPos:1219 yPos:643
<00039> 004904B2 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00040> 004904B2 R WM_WINDOWPOSCHANGING
<00041> 004F0646 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00042> 004F0646 R WM_WINDOWPOSCHANGING
<00043> 00340626 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00044> 00340626 R WM_WINDOWPOSCHANGING
<00045> 004904B2 S WM_WINDOWPOSCHANGED lpwp:0012FE20
<00046> 004904B2 R WM_WINDOWPOSCHANGED
<00047> 004F0646 S WM_WINDOWPOSCHANGED lpwp:0012FE20
<00048> 004F0646 R WM_WINDOWPOSCHANGED
<00049> 00340626 S WM_WINDOWPOSCHANGED lpwp:0012FE20
<00050> 00340626 S .WM_SIZE fwSizeType:SIZE_RESTORED nWidth:1280 nHeight:770
<00051> 00340626 R .WM_SIZE
<00052> 00340626 R WM_WINDOWPOSCHANGED
<00053> 004904B2 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00054> 004904B2 R WM_WINDOWPOSCHANGING
<00055> 004F0646 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00056> 004F0646 R WM_WINDOWPOSCHANGING
<00057> 00340626 S WM_WINDOWPOSCHANGING lpwp:0012FE20
<00058> 00340626 R WM_WINDOWPOSCHANGING
<00059> 00340626 P WM_PAINT hdc:00000000
<00060> 00340626 S WM_ERASEBKGND hdc:D1011D9A
<00061> 00340626 R WM_ERASEBKGND fErased:False
<00062> 00340626 S WM_GETICON fType:True
<00063> 00340626 R WM_GETICON hicon:1CA203B1
<00064> 00340626 S WM_GETICON fType:False
<00065> 00340626 R WM_GETICON hicon:00000000
<00066> 00340626 S WM_GETICON fType:True
<00067> 00340626 R WM_GETICON hicon:089A0417
<00068> 00340626 P WM_LBUTTONDOWN fwKeys:MK_LBUTTON xPos:1252 yPos:726
<00069> 00340626 P WM_LBUTTONUP fwKeys:0000 xPos:1252 yPos:726

The big difference is lines numbered 39-67. Does anyone understand what's happening here? And what is a correct solution for this problem? What causes it? It seems that i have to intercept the paint message to tell Windows to shut up. But what worries me is that the hdc is 0. 

Any help will be appreciated..

int main(int argc, char* argv[])
{
	
	boost::chrono::system_clock::time_point start = boost::chrono::system_clock::now();	
    ICaptureGraphBuilder2 *pCaptureGraph = NULL;	// Capture graph builder object
	IGraphBuilder *pGraph = NULL;	// Graph builder object
    IMediaControl *pControl = NULL;	// Media control object
	IFileSinkFilter *pSink = NULL;	// File sink object
	IBaseFilter *pAudioInputFilter = NULL; // Audio Capture filter
	IBaseFilter *pVideoInputFilter = NULL; // Video Capture filter
	IBaseFilter *pASFWriter = NULL;	// WM ASF File config interface

    // Initialize the COM library.
    HRESULT hr = CoInitialize(NULL);
    if (FAILED(hr))
    {
	     // We’ll send our error messages to the console.
        printf("ERROR - Could not initialize COM library");
        return hr;
    }

    // Create the filter graph manager and query for interfaces.
    hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, CLSCTX_INPROC_SERVER,
                          IID_ICaptureGraphBuilder2, (void **)&pCaptureGraph);
    if (FAILED(hr))	// FAILED is a macro that tests the return value
    {
        printf("ERROR - Could not create the Filter Graph Manager.");
        return hr;
    }

	// Use a method of the capture graph builder
	// To create an output path for the stream 
	hr = pCaptureGraph->SetOutputFileName(&MEDIASUBTYPE_Asf, 
		L"C:\\MyWebcam.ASF", &pASFWriter, &pSink);

	// Now configure the ASF Writer
	// Present the property pages for this filter
	hr = ShowFilterPropertyPages(pASFWriter);

	// Now get the filter graph manager
	// That's part of the capture graph builder
	hr = pCaptureGraph->GetFiltergraph(&pGraph);

	 // Using QueryInterface on the graph builder, 
    // Get the Media Control object.
    hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pControl);
    if (FAILED(hr))
    {
        printf("ERROR - Could not create the Media Control object.");
        pGraph->Release();	// Clean up after ourselves.
		CoUninitialize();  // And uninitalize COM
        return hr;
    }

	
	
	// Now create the video input filter from the webcam
	hr = EnumerateAudioInputFilters((void**) &pAudioInputFilter);
	hr = EnumerateAudioInputPins(pAudioInputFilter);
	// Add the audio capture filter to the filter graph. 
	hr = pGraph->AddFilter(pAudioInputFilter, L"Audio");

	hr = GetVideoInputFilter(&pVideoInputFilter, L"HP Webcam");
	if (SUCCEEDED(hr)) {
		hr = pGraph->AddFilter(pVideoInputFilter, L"Video");
	}

	// Add a video renderer
	//IBaseFilter *pVideoRenderer = NULL;
	//hr = AddFilterByCLSID(pGraph, CLSID_VideoRenderer, L"Video Renderer", &pVideoRenderer);

	// Use another method of the capture graph builder
	// To provide a render path for video preview
	

	
	IBaseFilter *pIntermediate = NULL;
	
	
	hr = pCaptureGraph->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video,
		pVideoInputFilter, NULL, NULL);
	
	// Now add the video capture to the output file
	hr = pCaptureGraph->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video,
		pVideoInputFilter, NULL, pASFWriter);
	
	
	// And do the same for the audio
	hr = pCaptureGraph->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Audio,
		pAudioInputFilter, NULL, pASFWriter);

    if (SUCCEEDED(hr))
    {
        // Run the graph.
        hr = pControl->Run();
        if (SUCCEEDED(hr))
        {
			// Wait patiently for completion of the recording
			wprintf(L"Started recording...press Enter to stop recording.\n");
			// Wait for completion.
			boost::chrono::duration<double> sec = boost::chrono::system_clock::now() - start;
			std::cout << "took " << sec.count() << " seconds\n";
			char ch;
			ch = getchar();		// We wait for keyboard input
			
        }
		
		// And let's stop the filter graph
		hr = pControl->Stop();

		wprintf(L"Stopped recording.\n");	// To the console

		// Before we finish up, save the filter graph to a file.
		SaveGraphFile(pGraph, L"C:\\MyGraph.GRF");
    }
	
	// Now release everything, and clean up.
	pSink->Release();
	pASFWriter->Release();
	pVideoInputFilter->Release();
	pAudioInputFilter->Release();
    pControl->Release();
    pGraph->Release();
	pCaptureGraph->Release();
    CoUninitialize();

	return 0;
}