1) How much hard drive space do you have available? Double-click your hard drive and look at the bottom of the window.
2) Do you need to keep all your photos on the hard drive? What happens if the hard drive fails? Do you have them backed up somewhere?
3) Do you need to keep all your music on the hard drive? What happens if the hard drive fails? Do you have your music backed up somewhere?
4) Why do you think it is running slow? What were you doing that brought you to this conclusion?
I would strongly suggest that you get 1 or 2 external firewire drives and offload the music and the images... the chances of the internal AND external drives failing at the same time are very slim... You can re-install applications - you will have a hard time recreating one-of-a kind photos or rebuilding your music collection. Hard drives are electro-mechanical devices measured using MTBF - Mean Time Before Failure. They are EXPECTED to fail.
There are a number of reasons for the slowness you are experiencing - the worst case (though not likely) is there are issues with the drive and your computer is trying to tell you someting. The likely case is you have less that 10%-15% of available hard drive space and your computer is bumping into itself trying to do work for you. You should NEVER EVER EVER fill a hard drive. You should ALWAYS HAVE at least a MINIMUM of 10%-15% available hard drive space. (This is not just a Macintosh requirement - any operating system will behave similarly if there is no available hard drive space...)
I lately have noticed that my iBook G4 14'' (mid-2005) OSX 10.4.8 has been running slow lately.
A quick check of iStat nano shows I have about 70 MB of free memory at the most, and down to 6 MB at the least. This seems very low. (Correct me if I'm wrong. I have 512 MB built-in. I have about 1100 photos, 900 songs, and not much else. What can I do to free up some memory?
Thanks.

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