I know we've (well mostly Leeky) have been working with you installing Ubuntu or a variation of it this whole thread. But, I've been thinking, maybe Ubuntu isn't what you want on there anyway....
Sometimes, for whatever reason, a flavor of linux just won't work on a specific computer..
For a computer that old, I really think you should try PuppyLinux. I've actually ran it on a P2 350 like yours before, and its incredibly fast.... Until you browse the web. Modern webpages actually use enough CPU that you'll notice it on a 350, but its not unusable (except for flash). Should work out well for you if it will install.
I think DSL will be too difficult because I think it is a lot more command line based.