Lion install fail

Ok this has been a nightmare. Going to try and be as thorough as possible.

I was running the lastest version of snow leopard. Downloaded lion last night to install. Tried to install and got an error saying "mac os x lion couldnt be installed, because the disk is damaged and cant be repaired"

So i restarted my computer to run the disk utility. I tried first aid on my internal hd, ran verify disk and got several missing thread record errors. It then said the disk needs to be repaired. Problem is the repair disk button is grayed out.

Figuring I have everything backed up on an external hd from time machine, I thought I would go ahead and erase the drive. Start from scratch. But when I try this I get an Volume Erase Error. Couldn't unmount disk.

Tried restore, couldn't get anywhere in there.

Tried rebooting from an install snow leopard 10.6.3 DVD by holding down C and it ignores that and goes right back into Lion install hell.

Basically that's the vicious cycle where I'm at. I have the first aluminum iMac g5 with a 250gb hd. I have no clue what else to do short off taking it to the genius bar. Any ideas?

 

Thanks for the reply. Holding option didn't work either. It's like this lion installer has totally hi jacked my Mac and there's no way out of this. I've even tried to do a time machine restore. No luck there. Wouldn't let me select my hd.

I tried quitting the installer which brought me to Choose Statup Disk. When I select my hd it gives me an error of You can't chane the startup disk to the selected disk. Startup disk could jot gather enough info on the selected disk.

 

Wow that might be the issue. If this is a first gen aluminum intel iMac it may not not be a core 2 duo.

Unreal. It sucks it won't let me go back to snow leopard though. I mean nothing has installed yet. Guess I'll just have to take it in. Thanks for the heads up.