Igor_G5 wrote:
... I thought about putting in a larger drive but when I looked up instructions for it i was surprized at how difficult it was.
Did you use the iFixit website? It has excellent pictures and instructions that are easy to follow.
Replacing any hard disk drive will be challenging for a paraplegic, but with someone's help it can be done fairly inexpensively. There are many tiny fasteners that require tiny tools. Use an egg carton to store them, separated by their location in the PowerBook.
Earlier PowerBooks are easier to work on than later ones.
I still use a PowerBook G4 on occasion, mostly for importing video for editing in iMovie. I upgraded its original 60 GB HD to a much larger one. If you were to do this you would need to locate the PowerBook's original System Install DVD to install and subsequently update OS X and all its original programs.
If you ensure at least a few gigabytes free space, I think most of your problems will be fixed. When free disk space gets down to a few hundred megabytes or less, performance will suffer dramatically. You don't want it to ever get anywhere near that low. Strange things start to happen.
Keep the number of icons on the Desktop to a minimum also. That makes a difference, for reasons that I do not fully understand.