Index: Modules/_testcapimodule.c
===================================================================
--- Modules/_testcapimodule.c	(revision 84639)
+++ Modules/_testcapimodule.c	(working copy)
@@ -11,6 +11,9 @@
 #include <float.h>
 #include "structmember.h"
 #include "datetime.h"
+#if defined(_MSC_VER) && _MSC_VER < 1400
+#include <crtdbg.h>
+#endif
 
 #ifdef WITH_THREAD
 #include "pythread.h"
@@ -2183,6 +2186,16 @@
 static PyObject *
 crash_no_current_thread(PyObject *self)
 {
+#ifdef _MSC_VER
+    /* PyThreadState_Get() will halt via abort(). Following function
+       call is needed to supress popup of the dialog box */
+#  if _MSC_VER >= 1400
+    _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
+#  else
+     /* XXX: abort() prints "abnormal program termination" */
+    _CrtSetReportMode(_CRT_ERROR, 0);
+#  endif
+#endif
     Py_BEGIN_ALLOW_THREADS
     /* Using PyThreadState_Get() directly allows the test to pass in
        !pydebug mode. However, the test only actually tests anything
Index: Python/pythonrun.c
===================================================================
--- Python/pythonrun.c	(revision 84639)
+++ Python/pythonrun.c	(working copy)
@@ -2086,7 +2086,7 @@
         PyErr_PrintEx(0);
     }
 #ifdef MS_WINDOWS
-    {
+    if (IsDebuggerPresent()) {
         size_t len = strlen(msg);
         WCHAR* buffer;
         size_t i;
@@ -2100,10 +2100,10 @@
         OutputDebugStringW(L"Fatal Python error: ");
         OutputDebugStringW(buffer);
         OutputDebugStringW(L"\n");
-    }
 #ifdef _DEBUG
-    DebugBreak();
+        DebugBreak();
 #endif
+    }
 #endif /* MS_WINDOWS */
     abort();
 }