You need the original installation disc for the operating system that you wish to install.You will also need the license or activation code for that computer.

What you have is
1) Boot Disc......this is a disc that is used to start an already installed operating system when the operating system fails to boot on it's own.
2) start up disc....see number 1 they are the same thing!

note****** a boot disc is also used to install recovery programs and utillities for performing repairs to an already installed operating system. or to build self booting installation discs of programs and operating systems. A start-up disc is usually designed to boot a specific operating systems when they fail.

what operating system are you trying to install? what hardware is installed on that computer? These are important questions that should have been looked at before you went and wiped the drive clean. Now it will be a bit harder in locating drivers for unknown hardware.