Install windows xp after windows 7

[zaki hissing]

my pc currently running windows 7, for reasons i want to remove windows 7 and replace it with windows xp again. my question is how to format the existing windows 7..tq

 

[hitechgowthaman]

You r already instal xp same procedure ,change bios settings into boot from cd or dvd ,put the cd restart system a hint 102501=100Gb accuratly then see how much gb balance some 45gb is balance create it into c drive for os