hi Rich. The linux on this machine is a somewhat tailored version of Xandros. It isn't a very good distro.
I found the best of all to be PCLINUX. Very user friendly, easy to install. Over here it is usually on offer in a linux computer mag. (of which there are many every month) and costs maybe 20$ with the mag. Linux has come of age!
Windows slowing down is usually due to not doing regular reg. cleaning and all the rest of the junk that accumulates. XP service pack2 is still the most reliable Windows to date. I don't know what, if anything, the latest service pack3 brings.