IMac – iTunes accidentally deleted on iMac G5 with OS X 10.4.11 – how to install iTunes

There are 3 more start ups you can try:

1. Press Option-Command-P-R until you hear startup sound a second time.

2. Press Command-V during startup. -Start up in Verbose mode.

3. Press Command-S during startup. -Start up in Single-User mode.

here is more detailed information what to do.

_{Start up your computer in single-user mode to reach the command line. 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.}

At the command-line prompt type:

`/sbin/fsck -fy`

• 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_of_volume) 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).

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

Your computer should start up normally and allow you to log in.

or see the link for more information.

I had the same problem, and managed to open .dmg files by going into Disk Utility>File>Open Disk Image. Once opened in Disk Utility, Double Click (Right Click) the icon and click show in Finder. Then I could install what I wanted! Hop it works for you!