Clean-up v. new computer

[J. Dobson]

Another question
   Although I'm pretty good at self-teaching myself software programs, I'm
not good with knowing how and why the insides of these things work (as
you'll see below). Also, working alone, I don't know who to bounce some of
these questions off of. Hope you don't mind and can give me some guidance.

I have a beige desktop G3 with 352 MB built in memory, with 266 MHz (is that
my problem?). I'm using system 9.0.4

I'm having lots of problems with the internet (slow, crashes and freezes) as
well as with other programs. Most recent is saying that I'm out of memory,
when I know I'm not (fragmented?) I'm also the one that lost my dictionary.
(How the heck?) 

What is the software or program that will de-fragment everything? Is that
available as a free download anywhere?

I'm thinking that the only thing I can do is copy everything onto CD's,
erase everything else (?) and then reload clean programs or something. Am I
right?

    VS. getting a new computer, which isn't really in my budget right now. I
started using Spring Cleaning, but could see that was going to be a 900+
hour process. Part of my problem is that I have two systems folders on here
(don't ask - I think it had to do with several office moves) and I don't
know which one to toss.

Gary, how can you test/know/trust purchasing a used computer or other
peripherals? I've often thought about it, but hesitate.

Any recommendations for low-cost CD-RW's? Too, how are these to buy used, or
given the importance of them (as my sole back-up) should I just buy new?

Thanks much for any guidance.
Jackie