New hard drive: how to set password!??

[Christopher]

The hard drive died on my mom's macbook, so we had a mac tech install a new one. It's a nice one but he installed 10.4.11 clean... i need to reinstall all her apps. Plus set up various accounts, etc. Can you tell me please how to do this without knowing the password? I have the original install disks for Tiger for this laptop, i can do a clean install.. but not without a password!

What do i do?

Thanks for any help.