First you want to figure out whether it's a hardware issue. If the drive still works just doesn't boot, that's one thing. If the drive is physically broken, then the approach to repair is entirely different. Plug it into a different machine and see if it still works. It sounds like that's what the tech tried and it didn't work, but who knows what it is that he did? If the drive is physically broken there is still hope but it will either be expensive or will involve a lot of work yourself. Basically you buy the exact same drive model and swap the platters.