Honestly, I wouldn't try swapping out a processor or a motherboard on a laptop. I ordered a series of laptops at one point and it turned out that they all had a problem on the motherboard and they started overheating (it turned out that the Intel factory that produced them had accidentally shipped a bad batch of motherboards to a series of manufacturers). A Dell representative came out to replace each of the motherboards, and she spent quite a bit of time (an hour or two) to do each, and she knew what she was doing. Also, in the process of that, two CPUs blew (she didn't set the jumpers back into place securely enough) and one laptop had to be scrapped completely and a new one had to be ordered because when the motherboard had overheated, it fried nearly all of the other electronics within the laptop.

In your case, I would just suggest stick with the 366 and 256 MB RAM. XP won't run on it, but 2000 should (albeit somewhat slow) if you're looking for better resource management. I would just be happy that you were handed down a laptop, and make the best of what you have.

If you really want a laptop to run XP, you had better go out and buy a more recent laptop. I personally wouldn't even try to run XP on a Celeron, let alone one anything below 600 MHz. Any machines I have that are below around 850 MHz and less than 512 MB RAM get Windows 2000 or NT 4, depending how slow the machine in question is. I reserve XP for machines which I know have the massive amount of resources necessary to it, and I would suggest you do the same.

AJ