Is my computer dead forever?

I have a Mac 10.4 purchased in 2007.

Several weeks ago I was watching a library DVD and it froze. I couldn’t force quit anything or eject the DVD so I manually shut it down. When I tried to reboot it, it showed a file folder symbol with a question mark flashing.

My computer whiz neighbor thinks it can’t find the harddrive and thought he’d be able to fix it with my startup disc. He tried that today, to no avail.

My neighbor suggested that the harddrive has changed so much through software updates that the installation disc no longer matches or something.

Ideally, my computer can be saved, or at least my harddrive can be found and moved to a new computer. Do you think a real computer place could fix it or will they have the same problems my neighbor did? Do repair places charge if they can’t fix it? Has this happened to anyone else?

Thanks a lot!