need help reinstalling install disk

I am having trouble starting up my imac. I did a disk repair and it came back saying 'error:the underlying task reported failure on exit. Volume 1 could not be repaired because of an error.' When I try to reinstall using the install disk it says 'this software cannot be installed on this computer.' This is my original install disk, so I don't know why its saying that. Anyone have any ideas?

G'day and welcome to the forums.

Tell us about the install disc. 110% absolute guarantee it is the disk that came with that computer? They can, and do, get mixed up. First up suggest boot from the disc one, and leave Installer and go into Utilities and run Repair Disk and see what is reported. Maybe the drive has failed completely.

I'm 1000% sure this is the correct disk that came with my computer. Actually I hv had to do a total erase and install about a year ago using that install disk. When I did the disk repair it show that an error occurred on exit. So something's wrong there, I don't know what. I ran the disk repair a few times.