New iBook Running Slow...

So, I recently (few months ago) bought a used iBook. When I first got it the machine was running fine, but recently I feel that it has started to run a little slower than normal. Is there anything I can do to bump up the speed?

I.e. Like a defrag for a PC.

Is the computer slow or only the internet?

Little bit of both, I would say mostly the internet tho, and iChat...

download Onyx. it is a utility program that can clean up and optimize your hdd.

What's the processing speed and RAM you have installed on your iBook?

...Nevermind...Apparently I'm in retard mode today...
What operating system do you have installed on it?
This might spark up some "nay-sayers" but....
I know a 1.33 iBook CAN support leopard but...BUT
When I had a 1.42 GHz iBook, everything ran A LOT faster on Tiger than Leopard.