Help! Windows is corrupted

Hello, Windows isn't working properly. I can't open itunes nor install or uninstall without it saying it has a problem. So I've relieved it's a problem with windows and I've tried litterally EVERYTHING to fix it; when I try to install new windows 4.5 an error message will occur, when i try a clean up system that I have to download it will say 'an error has occured' , and every time I think I solved the problem an error will occur along the procces. Please, I need hel; I've tried all of the following:

https://support.microsoft.com/en-us/help/2438651/how-to-troubleshoot-windows-installer-errors#reso1
https://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=8483
https://discussions.apple.com/thread/1579589
https://support.microsoft.com/en-us/help/828376
https://social.technet.microsoft.com/Forums/en-US/home
https://answers.microsoft.com/en-us/windows/forum/windows_vista-system/windows-vista-is-not-working-properly/d74c992c-6854-4bc3-8e81-5fe23eafb4b6