IMac G5 tries to start and dies after spinning cog for a minute

Question

iMac G5 tries to start and dies after spinning cog for a minute
I did this;
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
the result was.
the 'permissions' are sometimes wrong, but they repair
the hard drive is either repaired or OK
the iMac will then restart and work fine and sometimes shut down and restart OK
after replacing the Hard Drive I actually thought I had fixed it and went to bed late but happy,
on waking in the morning, however I was not so happy it fired up and then died after dong -> apple logo -> spinning cog -> dead!!
I would be grateful for any help
Thanks
Pete

Answer 1

Hi Miriam,
Thanks yes,
here we go -- after running disc utilities it tells me directory OK and disk OK (or something like that) When I replaced the Hard Drive, I started 'fresh' erased/formatted the hard drive (new Seagate Barracuda 7200 500GB) and it has just got 'tiger' on it (and upgraded to whatever it is now I think I remember 4.11, I can't tell at the moment as I have got the back off) I didn't transfer any data I just took the old drive (Seagate 160GB) out and stuck the new one in.
I've just changed the battery (I didn't really think it would work, but I was still hopeful and I'd bought the battery anyway) I did the LED thing, the internal power button thing, and the resetting the SMU thing (with crossed fingers and bated breath) but -- so I'm thinking is it the power supply? I read some of Jim's weighty, but worthy tome and resolved to remove the power supply and have a look. On opening it up, it does look as though, one (at least) of the capacitors has 'blown' (by the way, just in case I sound like I know what I'm talking about, I don't of course, I'm just quoting Jim's words;-) I'd love to send you a picture of the inside of the power supply showing what I believe to be a 'blown' capacitator (and I'm going to try to send one to Jim as I think it might be useful to him and others. can I attach a photo in any way or would you like to send me your email address <Edited by Moderator>
Thanks
Pete
PS it's still 'weird' to me, why it starts and runs well, when started from tiger (or whatever) and then starts or restarts from the Hard Drive unless I leave it a few hours and come back and try to start it
again? wow it's late nearly 4.00am here in london UK.