Why executing invalid instruction does not terminate my program?

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C++

Windows

I program in VC++, I put an invalid instruction such as

*(long*)0=0;

In the window proc of my dialogs. for some messages such as VM_INITDIALOG this instruction causes an access violation writing at location 0X00000000 as expected. But putting any invalid instruction in most messages such as WM_PAINT,... does not terminate my program and this causes me not to notice bugs in my program. can anyone tell me why is this?
This problem did not accure when I used Windows XP and Windows Vista on 32bit platforms.
I use Visual Studio 2008 32bit on Windows7 64bit and my hardware is HP notebook DV6-2020EV