I have windows xp bootable media in my pendrive. But when I boot into it, it doesnt show anything and it continue to startup windows 10 instead.
No such thing as USB bootable XP install, it just doesn't work.
If your computer is newer than Sandy Bridge, do not try to boot XP in a full environment because it simply won't work, too many driver conflicts. You should run it in a virtualized environment as USAFRet said.