Are you sure you don't have any viruses or startup programs/processes that are bogging it down? With a processor that slow, little things could really slow it down, especially seeing that it's a single core and at those temps.
I just did a clean install of xp and installed avg this morning after swapping hds and so far no freezes and the system is a lot faster. I don't know if the temp will be an issue in the long run because it now runs at 40c idle and 50ish when under load and over the summer that part of the building is uninsulated and gets direct sun light for most of the day. So come july that computer will be pretty much sitting in an oven.
the computer doesn't freeze when you use it anymore however if it is left for a day or so sometimes when you move the mouse to turn the monitor back on it won't and needs to be reset.
the computer doesn't freeze up when you use it anymore however if you leave it for a while and come back when you wiggle the mouse to turn the monitor back on it won't and will need to be reset