Something that hasn't been addressed here - but which probably should be - concerns the security implications of running a network for somebody like me who is living dangerously and still running XP I am guessing that it is most likely not exactly a good thing to do!
I have disabled file sharing again for the time being. It doesn't really matter to me tbh, it is not something that is vital for me to use. I just really wanted to know how it is done and whether I personally could work out how to do it! I just enjoy learning new things where the computer is concerned and it was great fun doing this on Monday. I won't be heartbroken though if I am told I should not use it at all!