simple and sweet here is the code: .386 .model flat, stdcall option casemap:none include \masm32\include\windows.inc include \masm32\include\kernel32.inc includelib \masm32\lib\kernel32.lib include \masm32\include\user32.inc includelib \masm32\lib\user32.lib .data msg db "Hello world!!!", 0 cpt db "MY FIRST PROGRAM!!!", 0 .code start: invoke MessageBox, NULL, addr msg, addr cpt, MB_OK + MB_ICONINFORMATION invoke ExitProcess, NULL end start