only see small folder icon in center of screen when power up

I think that's a question mark in the folder. It means that your computer can't find a system folder. This is either a corrupted system or a failed hard drive. Try starting up from the installation DVD by holding down the "C" key and booting with the disk installed. Go to the second screen and the pull down menu will appear. Go to Utilities - Disk utility and see if your hard drive comes up. If so repair it. If not let me know and we'll go through hard drive replacement.

Here's a few of the hard drives iFixit has for your machine: http://www.ifixit.com/Mac-Parts/iBook-G4...

Here's how to install it: iBook G4 12" 1.33 GHz Hard Drive Replacement