Why can't I load windows xp

When I cut my laptop on it says error loading windaws it won't let me do anything this was my Nieces laptop she sent out to me and she forgot the class word its like 3 or 4yrs old how can I reset it like factory condition or reset windows to load please help me its a perfectly good laptop andci don't want to put it in a shop andcpoay acfortune to get it fixed thank you for your support in this matter my phone is 540-3954344 my email address is trishpritc@gmail.com