Factory Reset iMac G5 Power PC

Hello!

I'm trying to factory reset my old iMac G5 Power PC computer.

I want to give it away and I want to erase all data safely and reinstall the operating system.

I have the 2 x CD's that came with the mac.

So far I've erased all data but not on recovery mode. I've also reinstalled the OS X from the CD. What I'm not sure is if that is enough or should I do it from recovery mode.

I've tried to put the computer on Recovery Mode but it doesn't do it. I've tried Command + C, R... all possible combinations I've found around. Nothing seems to work.

Any suggestions?

Thank you!