I can't update OS X

[Reasonable Man]

Hi,
I am a fairly new Mac user and have an iMac8,1 with an Intel Core 2 Duo 2.66 GHz Processor. It has Mac OS X Version 10.5.2.

My iTunes told me I had to update that version but could not until I had updated my Safari to Version 4.0.3 (I currently have v3.0.4). When I tried to install this it said I needed OS X v 10.5.7 to do so. I went via Software update to find that v 10.5.8 is now available so downloaded that. My computer will not install it though. When my computer starts it goes through the initialising process and the blue line of progress just stops. I left it installing for 3 days as I went away but on my return there was no progress.
I then back to the Apple site and downloaded 10.5.7 in case I had to install that first but when I go through the installation process it stops at Destination Select with the advice, 'You cannot install Mac OS X Update on this volume. This volume does not meet the requirements for this update.'
Macintosh HD is the only volume I have.

How do I update from 10.5.2 to 10.5.7 (or 8)?
Thanks

 

[Walrus666]

Hello, If you haven't done so, repair permissions before installing the update.

 

[Reasonable Man]

Hello, If you haven't done so, repair permissions before installing the update.

Thanks for the reply Walrus.
Just found out how to repair permissions, do so but no joy. Still getting the same message.

 

[Walrus666]

Try placing the "com.apple.SoftwareUpdate" folder that's in your Library-Cache's folder in the trash, and REBOOTING. Then try updating again.