Since it is locked down, your best bet is to get a 10.4 retail or 10.5 retail as described below.
If you can verify it is 1 Ghz or faster, you can get the 10.5 retail installer. You have a much better chance at making this usable machine with one or the other, than 9, since 9 discs are hard to come by, and very little software is written for 9 anymore. Just make sure you have at least 256 MB of chip RAM for 10.4, preferably 512MB, and/or 1 GB of RAM for 10.5. Use these tips to
https://discussions.apple.com/docs/DOC-2541- decide if 10.4 is sufficient.
https://discussions.apple.com/docs/DOC-2275- decide if 10.5 is sufficient.
Get the Mac to set up an additional administrative account. You can then change the password on your old account.
Start with your computer power off. Hold down command-s. Power on your computer.
Type in the following:
The first two commands will depend on your release of Mac OS X. Look at what is typed out in the console to determine the exact format.
# Type the follow two instructions to access the startup disk in read/write. Press return after each command.
/sbin/mount -uw /
#List all files. The l is a lower case L.
#The move command acts as a rename command in this format.
mv -i .applesetupdone .applesetupdone.old
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!!
Limnos adds detailed explainations:
The above the idea came from a post by JoseAranda at September 9, 2006 3:48 AM
You will need to scroll down to see this post. Search for applesetupdone
Once you have a new administrative account, you can change the password of your old administrative account
blue apple > System Preferences > Accounts
-- You can see that it is easy to change your administrator password. You can set a firmware password that you enter before your machine will boot.
-- For the best data security, you should use FileVault. Create a good logon password. Define and use a good backup plan. I do not recommend using FileVault unless you really need the security because it is much harder to recover your data should you have a harddrive problem and you do not have your data backed up. data should you have a harddrive