G5 Powermac Wont Start

Hi,

I've had a few problems with my Powermac G5 which resutled in me flattening the machine, buying a new 500gb hard drive and OSX leopard and starting from scratch.

I migrated info from my G4 and all was running smooth for about two weeks. Then i started getting the odd problem when starting up. I always start as main user but every so often it would ask if i wanted to start in another user, then wouldn't let me in as the main user. I would restart and no problems go straight in to the main user.

then i had a few issues where it wouldn't start at all first time, second it would.

Through all this disk utility is telling me the all disks including the hard disk 'appear to be ok'.

Today it won't start at all. Grey apple screen then dark grey with the box saying i must restart which is the problem i had before and ultimately what made me flatten the machine and buy the new HD last time!

I can start with the leopard install disk, run disk utility but all appear to be ok on all disks again - the only problem i can find says group differs on private/etc/cups on repair permissions.

I can also access all drives from my G4 by starting the G5 in target mode.

Can anyone offer any help? Is there anything other than the hard drive and osx that can be replaced to fix my problem?? I am no techy so please use simple terms.

PS: 10.5 leopard is the OS, and i did the latest upgrades when i rebuilt it so it is on latest version - 10.5.3 i think!

It could be just a loose cable. Open up the mac again and make sure all cables are securily in place.

i have checked all the cables i can see and all are secure.

I've also reset the button behind the fans (forget its proper name sorry) and taken out and replaced the PRAM battery