Normally there is only one OS installed at a time.
Usually it is installed on your HDD (Hard Disk Drive).
One original OS only for one computer
None. Mac OS X can only be installed on an Apple () computer.
What installed on a computer which determine how data is processed
If you have os x lion for mac
No. The printing capabilities are accessed on a computer by installing a standard OS (Operating System). Usually this feature is included in the purchase of a computer because the OS is pre-installed.
Dual Boot
It can no longer be purchased unless you get an old used computer with it already installed.
The drive that the OS is installed on
Providing the Intel processor is in an Apple Mac computer, and the rest of the computer parts are present too, then Mac OS X can be installed.
Mac OS X can only legally be installed on computers made by Apple.
The installation CD of the new OS should be bootable. Boot the computer with the disc in, and choose to install the OS. It should give you an option to clean install, and format.