This the example from Iczelion s Win32 Assembly Tutorial part 24. In order to assemble the example, you have to have ml.exe, link.exe and nmake.exe in your path. If they re not in the path, you will have to edit makefile to include the full path. You ll have to edit the makefile to correct the path to import libraries in your PC. Type nmake in the same directory as makefile and the assembly process will begin. If you don t want to use the makefile, you can manually assemble the example with the commands below: ml /c /coff /Cp mousehook.asm link /SUBSYSTEM:WINDOWS /LIBPATH:c:\masm32\lib mousehook.obj