https://passionford.com/forum/computers-consoles-and-i-t/183129-step-by-step-guide-as-to-how-to-repair-windows-xp.html

Look in the Computer room and you can get 90% of your answer

Link above shows a repair. Instead of the repair option go for a fresh install (Press Enter instead of R)

Then press escape to not repair, delete all partitions (It will show on the screen what letters you need to press)

Then just follow the instructions.