My Early 2008 iMac with OSX 10.8.5 no longer boots beyond grey screen with spinning gear. Verbose mode shows a load of I/O errors. Disk Verify/Repair run via recovery partition completes successfully, as does
fsck terminal command in single user startup mode (it modified the files on first run but not second). I reset the NVRAM too.
However none of these have helped, same I/O errors afterwards. Thinking it might be due to OS files being corrupted I created a USB drive with installable version of OSX (actually 10.9 Mavericks), but it crashes during install.
I wanted to try Apple Hardware Tools diagnostics but the startup shortcuts D or opt+D don't work - I read it's been removed so presumably I'll need to find a way to reinstall it first. I've tried the usual fixes such as safe mode (won't boot), removing all peripherals, even the RAM sticks. I can't hear the drive making any grinding sounds.
Is there anything else I can try to fix this? Is it likely the HD has died even though Disk Repair is returning success?