i am having trouble booting up my windows xp disc from a rebbor of my pc

I am wanting to reinstall my windows xp so i can format my drive.i have a copy of windows xp when i put the disk into my drive and reboot my pc so i can boot from cd at start up i am not getting the option to do so.can someone please help is there anyway i can get the disc to boot up when my pc reboots i would be very grateful for your help thanks

 

Your BIOS must be set to boot from CDROM first in the boot sequence.

 

thanks for the advice it works a treat now