In reply to Frankie boy:
I'm going to join the others and say that a suitable Linux distribution will let you get the most out of this laptop. Over the years I've had great success moving over 8-10 year old machines and getting another 5+ years out of them. It's not for the fainthearted though, it'll be a faff to install and a steep learning curve to get used to using it. If you're into computer-y things and like experimenting, then go for it, it'll be fun.
A less time consuming option would be stick with Windows XP, switch off all the features you don't need, and be careful about browsing/downloads so it doesn't get a virus. You might also get some speedup by running the disk cleanup tools, defragmenting from time to time (man, that takes me back), switching off the plastic-toy graphics in favour of old school win2000 style, disabling unwanted startup items in msconfig, and turning off file indexing (if you don't do file searches very often).
Also bear in mind that although it may have run Firefox just fine 10 years ago, firefox of today is not firefox as was. So you'll benefit from finding lightweight versions of any applications you want. You can also just run older applications (e.g. Office 2010) but I wouln't recommend that for a browser for security reasons.
Post edited at 12:16