I followed the instructions to take ownership of the iTunes folder. I rightclicked on take ownership of the folder but nothing happened. No message that ownership had been taken, or something like that, and I still Could not open iTunes. So i rebooted the computer. As it Was opening up, the message "Non-System disk or disk error, replace and strike key when Ready" came up, and I can not start the computer anymore. When I run system diagnostics, I get the answer that the disk is not installed.
I am worried that my hard disk is dead and that all My information is lost. I need guidance, thankfull For all your help!