Confusing:
you said you can't reinstall:
Is it possible that you have a bad OS X install disc????
😕 It could either be a damaged OS X install disc, or it could be a model specific disc....
There aren't any ibook G5 and powerbook G5. The

G5 product line was a very short lived release.
Your descriptions of your computers are very confusing.
😕 "white with no camera" is not very helpful. As for imacs...they at one time have complete redesigns. The G3s have transparent colorful cases with CRT monitors in them. The G4 imacs have LCD monitors and almost look like a desk lamp. Somebody also has described the base of a G4 imac as a "bowling ball cut in half". The G5s and intel imacs look like regular LCD monitors.
Could you look at how your computers are shaped, and then describe them better?
It could also be possible that these computers have hardware problems, something installed In-Correctly, corrupted hard drives that have either physical or directory damage, or hard drives with low disk space. ....as described in the links that were provided to you.