toshiba laptop hard disk replacement

I have replaced my loptop hard drive . Bios sees the hard drive . I format the hard drive when boot up displays no operation system found. Please advise.
Regards

If your installing XP, boot off the cd and format the drive when windows asks. Then procede with the install. If you have the origional install disks that came with your laptop you should be able to restore it that way. You may have to change the boot order in bios to boot from cd. Let us know.