Can't upgrade software

"Try Disk Utility

1. Insert the Mac OS X Install disc, 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 at the top of the screen. (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. Select your Mac OS X volume.

5. Click Repair. Disk Utility checks and repairs the disk."

http://docs.info.apple.com/article.html?artnum=106214

Then try a Safe Boot, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, reboot when it completes.

(Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive.)

If there was any corruption you may need to download a new copy.

Are you trying to update via Software Update while on-line? Or did you download the .dmg file?

I've found it's best to download the file & install off-line. Get the combo update at http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update

 Cheers, Tom 😉

You mention Disc 1 & Disc 2. A Leopard installer comes on only one disc, a DVD that looks like this.

What discs are you using?

 Cheers, Tom 😉

When I try starting up from the disc (install disc 1), it will not let me. I get the 'banned' sign.

Maybe you have Firmware password protection setup in Mac OS X ...

http://support.apple.com/kb/HT1352

It would block usage of all the startup keys, like C, N, T, D, CMD+s, CMD+Option+p+r, CMD +v, Option, and Shift, as well as booting from anything but the Hard Drive.

Well, when you boot with the Option/alt key held down, do you see this?

If so you don't/cannot use the Install Disc to change it, boot normally then...

1. For Mac OS X v10.4.x, you must use the updated version that can be copied from the software installation disc (located at /Applications/Utilities/ on the disc).
   For Mac OS X v10.5.x, start from the Leopard Install DVD and choose Firmware Password Utility from theUtilities menu, then skip to step 5.
2. Open the Open Firmware Password application.
3. Click the icon to authenticate. Enter an administrator username and password when prompted.
4. Click Change.
5. Click to unselect the checkbox for "Require password to change Open Firmware settings", as shown below.

I boot using alt key and get the two icons of the hard drive and the disc.

OK, then we don't have to worry about Firware Password, it's not installed.

What is te 2z691-****-A number on the Install Disc?

Hmmm, did that come with the Mac Pro, do you have Disk one?

Here's my info on that Disc, it's #2 which may work on other macs but isn't the Install Disc to start the Install...

For Mac OS X 10.5, Build 9A3129

Part number Description

2Z691-6150 Multi CPU Install DVD1 with 10.5

2Z691-6175 CPU INSTALL DVD 2

iMac (17-inch Late 2006 CD)

Model MA710xx/A iMac 17-inch D1.83G/512/160/Combo

Apparently that is an Upgrade Install Disc Requiring 10.4 be on there first...

http://www.welovemacs.com/2z6916150a.html