Running OS X, V10.4.11 on my new/used MB

[arlenehp]

I just bought this computer. It's a 13" Macbook, 2.16 Gh w/2GB.
I have been able to change the name of the computer, but have no way to change the password in order to add some programs.
Is there any kind of easy fix since I don't have the original disks? Or if I buy the snow leopard, and do a clean install, can I then change the password and name?
I'm not too savvy about computers but I'd attempt most any fix. If I can't my daughter in law is good at it, but she doesn't know what to do now either.
HELP!
Arlene

 

[DarkestRitual]

That should do the trick.

 

[6string]

That should do the trick.

I think what Darkest ritual is referring to here is Snow Leopard clean install....
This will do the trick.
However, you will lose iLife and iWork which don't come with Snow Leopard unless you buy the box set.