i have a couple year old g4 laptop with 80 gig internal memory. i only have about 7 gigs free and i know i should never go beyond 60 gigs used. how do i view how the memory is allocated so i can clear out old files and things i am not using. is there a way to optimize performance of the machine, defrag, etc.
All you have to do is erase things you don't need. If you need everything, back-up stuff you don't need that often onto CDs, DVDs, or external firewire hard drives before you erase them.
That's about all you need to do.
I'm not sure what you mean by seeing "how memory is allocated." You can click on the drive and hit Apple-i to see how much space is being used, but you already know how much space is being used. What else are you trying to find out? If you can explain that a little more specifically maybe we can help you, but really, just clearing up space is all you have to do.