repair dir in imac g5 17' leopard

How did you identify the problem with the root directory? What error message? What problem?

The root account is a special account for the super user. On mac os 10.4.11, it is /var/root

The root account isn't enabled by default. You have to do this manually & should not do unless you know what you are doing.

When you do a safe boot, the system will repair the filesystem.

Shutdown your machine. Hold down the shift key. Poweron. Wait awhile Wait awhile while you harddrive

is being checked.

http://support.apple.com/kb/ht1455

also,

you can do it manually. This is caused single user mode. If you file system is corrupted this may help. If you messed up /var/root you will need to describe in more details. root account isn't enabled automatically.

You need to get into single use mode for steps one and two that are listed below.

This page will tell you how to get into single user mode.

http://support.apple.com/kb/HT1492

Basically, you hold down the command-s key then powering on your machine. The command key has a little apple symbol on the lower left. It is between the alt/option key and the space bar. On a PC keyboard, it will be the windows key, I think.

( Do you know Unix. You are in a Unix single user console. ) The setup commands you need should be listed on the screen. For Mac OS 10.4.11, the commands are:

# Type the follow two instructions to access the startup disk in read/write:

# ( in case of partial success repeat this command until errors go away. )

/sbin/fsck -fy

/sbin/mount -uw /

# reboot your mac

shutdown -r now

I suspect the filesystem has become corrupted. This could be that you hd is failing.

Try single use mode. Will check out and correct filesystem on hd.

This page will tell you how to get into single user mode.

http://support.apple.com/kb/HT1492

Basically, you hold down the command-s key then powering on your machine. The command key has a little apple symbol on the lower left. It is between the alt/option key and the space bar. On a PC keyboard, it will be the windows key, I think. The boot up will take longer than normal. The filesystem will be checked and repaired.

# reboot your mac

shutdown -r now

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Apple may still supply the original restore CDs/DVDs for a nominal fee. Have your serial number and model information available when you call them. You do not have to be the original owner.

Restore Tiger 10.4 & Leopard 10.5 DVDs are available from Apple by calling 800-767-2775 as of January 20, 2013.

https://discussions.apple.com/thread/4720126?tstart=0

PS. Do not type in all upper case. It is harder to read and implies that you are shouting at the reader.