it chimes, logo, spinning wheel and then it shut off?

i have the same problem but i do not have the discs!!!! what will i do?? where can i get the disc...

O sx 10.8.5

Sounds like the problem I am currently rectifying. I have an iMac G5 1.8Ghz model and same thing boots to the logo and spinning spinning and shutdown. I managed to get it booted into disc warrior and started a repair and it locked up. So I decided to use Techtool Pro and successfully did the repair. I repaired 3 times back to back to ensure it was good. After the repair I lost the visual of my HD on boot and got the little man wondering what to boot to. So Now I have booted into my installation disc and and currently formatting and will proceed to reinstall. If all goes well it should get through. If not I will have to go buy a new hard drive and swap. If that fails, by by logic board. I suggest you keep in the back of your mind that if it is not bad sectors and repair doesn't work. Check out a new hard drive, keep in mind what type you need. If that fails then hit up a logic board. Google does wonders. I figure buying new hard drive and if necessary logic board it is still cheaper than an apple retailer fix. $300 to replace the HD. Ca you imagine on cost for both HD and LB??

I am not an Apple Guru. I play the wing it game, but I do some homework first. Much cheaper this way. I know I just cluttered everything into a long paragraph but I hope my info helps.