|Try the power cord with the battery removed. If the battery is bad then this may prove it if it starts.|
If you have a laptop with XP on it then it is probably quite a few years old, I had a desktop for over 9 years with XP on it but laptops generally are not good for half of that so do not plan on spending too much on it. If you have it at around 4 years or more then consider replacing it.
You have to be a little bit crazy to keep you from going insane.