System preferences-security and privacy-allow applications to be downloaded from the following locations-and then click on any source to open it.

The ITunes function that comes with macos is very powerful and easy to use. The player used under win is almost useless under macos.

Win78 10 Restore the system, right-click the computer and select Properties, and select System Protection and System Restore on the right. Follow the steps. If you have recovery software, you can also use software and image backup to recover the system.