Installed 10.4.11, stuck at Apple Logo screen, cannot re-install OS X.

Hi MVB1837, and a warm welcome to the forums! 🙂

I even tried using my MacBook Leopard disk and that did not work either.

Won't ever work it's a Machine Specific disk.

I booted up the ol' iMac to use in the meantime.

How old, which exact iMac please?

Tough without the Install disc, but some things to try...

Does it boot to Single User Mode, CMD+s keys at bootup, if so try...

/sbin/fsck -fy

Repeat until it shows no errors fixed.

(Space between fsck AND -fy important).

Resolve startup issues and perform disk maintenance with Disk Utility and fsck...

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

Tough without the Tiger Disk problems, but try fsck...

To use fsck, you must run it from the command line. Unlike using your mouse to open an application to do something, you'll need to type a text command at the prompt (#) to tell fsck what to do. The Terminal application (/Applications/Utilities) and single-user mode are two examples of command-line interfaces in which you can type such commands. To use fsck:

1. Start up your computer in single-user mode to reach the command line. Hold CMD+s keys down at bootup.
Note: If necessary, perform a forced restart as described in the Emergency Troubleshooting Handbook that came with your computer. On desktop computers, you can do this by pressing the reset/interrupt button (if there is one) or holding down the power button for several seconds. On portable computers, simultaneously press the Command-Control-power keys. If your portable computer doesn't restart with this method, you may need to reset the Power Manager.

2. At the command-line prompt, type /sbin/fsck -fy

3. Press Return. fsck will go through five "phases" and then return information about your disk's use and fragmentation. Once it finishes, it'll display this message if no issue is found:

The volume (name ofvolume) appears to be OK 
If fsck found issues and has altered, repaired, or fixed anything, it will display this message:
 *** FILE SYSTEM WAS MODIFIED *** 

Important: If this message appears, repeat the fsck command you typed in step 2 until fsck tells you that your volume appears to be OK (first-pass repairs may uncover additional issues, so this is a normal thing to do).

4. When fsck reports that your volume is OK, type reboot at the prompt and then press Return.

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

Then Safe Boot , (holding Shift key down at bootup), off the HD & use Disk Utility from there to Repair Permissions, reboot once more.

Since holding C, Option, etc is not allowing the computer to boot from the original disk, is this perhaps the computer failing to recognize the keyboard?

Yes, very well could be.

Wireless KBs may not be seen early enough in the boot process.

Firmware Password setup will prevent boot keys from working.

The KB on the Book doesn't work either?

We're stuck bigtime if no KB is recognized!

I just came here to post about the exact same problem: older iMac (G4 15" flat panel) that I seldom use, I let Software Update install the latest updates (10.4.11, Safari, Quicktime, and iTunes - I think), and now it gets stuck at the initial Apple screen - won't boot from my Tiger CD & won't boot in single user mode. I've tried switching the keyboard's port and switching to two entirely different keyboards with no success. I still love that little old swivel-headed iMac, so I'll be anxiously watching this thread for any further helpful ideas.

Nope, unfortunately not. Please don't forget to post if you find out anything helpful - I'll be happy to do the same. Good luck!

Another possibility for everyone here...

applesetupdone...

http://discussions.apple.com/thread.jspa?messageID=6059333&#6059333

http://www.askdavetaylor.com/howdo_i_reset_my_mac_os_x_admin_rootpassword.html

This was Posted by: JoseAranda at September 9, 2006 3:48 AM

"OK, restart your computer, hold down Command-s and type in the following:
/sbin/fsck -fy Enter
/sbin/mount -uaw Enter
rm /var/db/.applesetupdone Enter

1. The rm command is the remove command which deletes the file.
2. Robert: I'd rename the file via: mv /var/db/.applesetupdone /var/db/.applesetupdone.old

reboot Enter

Once you've done that the computer reboots and it's like the first time you used the machine. Your old accounts are all safe. From there you just change all other account passwords in the account preferences!!
end of posted by: JoseAranda"

Yeah, try another KB, or put this one in FireWire target disk mode...

http://docs.info.apple.com/article.html?artnum=58583

if you have another Mac around & can get it to recognize a t key!?