imac dead? I need help

[stege]

Hi everyone,
i'm soooo desperate!

this evening I was using the imac as always and the fans where going very fast. I decided to turn it off and on again. It never started again
I'm using Lion on an imac 27 late 2009

First: this is what happened http://www.youtube.com/watch?v=lpiBgXQCJ4k
a loading bar and then the imac turns automatically off.

what I did: first I did a Reset of SMC. Now Everytime I turn on the mac the fans are really at maximum speed. Still nothing, after a while it turns off.

Second step: tried the recovery hd. Pressing the option I entered the recovery hd from lion. I could check the permissions (but not repair the disk) and everything was ok.
I tried to reinstall lion from there but the only disk it showed was the recovery disk itself (marked as protected) and nothing else. It could not see the main HD (even if from the disk utility I could see the main disk (but not repair it))

Third Step: I tried reset PRAM. Now we are in deep ****. Now the screen is BLACK. Is not turning on anymore. I press the botton, the fans starts, the "boing" play but the screen remains black. And after a while the mac turns off.

I don't know what to do anymore.
At least I would like to have access to the HD, before sending it to apple.
I tought about formatting everything and reinstalling Lion but now that the screen in black every hope is gone...

Any advice what to try?
thanks!

 

[stege]

Update: now the screen is back! (i've removed the extra ram that I added one month ago and now the screen is alive again)
I can access the remote disk of lion, but cannot reinstall lion (says that the disks are both protected).
I could try erase everything from disk utility. What do you think? Shall I proceed?

 

[Detrius]

Boot in verbose mode. It will most likely show you that fsck is running, and then right before it shuts down, it will show you that fsck failed to repair the damaged directory structure.

You may have a bad hard drive. If not, you'll need something like Disk Warrior to repair the damage to the directory structure.

 

[stege]

I just woke up.
During the night I made an initialization of the disk and now I'm reinstalling Lion from recovery disk.
Is there any way to detect if the Hard disk is damaged? I would like to avoid to be in one month in the same situation after I have reinstalled everything...

 

[Detrius]

If you formatted the drive, then the log entries are gone. You'd need to run a proper surface scan.