I have an iMac that turns on, but does not boot up. I used to belong to a business that did post productions for TV studios. It has great specs and I would love to use. Having trouble reloading propper IOS.

我有一台iMac，能开机但无法启动。我以前在一家为电视台做后期制作的公司工作。它的配置不错，我很想用它。不过重装正确的系统时遇到了麻烦。