I have inherited an iMac with OS 10.6.8. It also has DeepFreeze installed and, of course, nobody knows the password. I know the only way to overcome this issue is to wipe the HD clean and reinstall the OS. But, I'd like to get it accomplished without cracking open the case. Command-R won't work because the OS is too old. I'm not able to create a bootable USB media on this machine because I don't have the Administrator PW. How do I wipe the HD clean and install a new OS (El Capitan?) without physical access to the HD?