In addition to what @SP. has written, can you also tell us exactly which version of MM you are attempting to install? MM 2021 is 64 bit only; is your computer running a 64 bit version of Windows? It is also possible that the fact you are still running the now unsupported Win 7 is a factor in this situation.
The minimum specifications for running Music Maker 2021 are listed on this page. You will see that Windows 8 is the "oldest" operating system for which the software is designed. I suspect the fact you are still running Windows 7 may be a contributory factor to the problem you are seeing.