Of course cannot
Providing the PC has been made by Apple then it is perfectly legal to run the Mac OS on it. The legal terms and conditions for Mac OS X prevent it being used on non-Apple hardware.
Mac OS X can only be installed on Apple hardware so Vmware is unable to support Mac OS X on anything other than a Mac by running, for example, a virtual installation of Mac OS X Server on a standard Mac OS X machine. Conversely Vmware's Fusion allows the running of Windows, and other operating systems, on an Intel Mac running Mac OS X.
Mac OS X is an excellent replacement for Windows 7. You can use Apple's Mac OS X on computers made by Apple. The legal terms you agree to when installing Mac OS X prevent it being installed on non-Apple computers.
Mac OS X (say Mac OS Ten) is the tenth version of the operating system (OS) that controls a Macintosh computer (known as a Mac for short). The equivalent for some other computers would be the Windows operating system. Mac OS X has been around for nearly ten years and replaced Mac OS 9 which was the last version of what is known as the "classic" Mac OS. Although a few Macs still use Mac OS 9 all Macs sold since 2002 have come with Mac OS X and would now be considered a regular Mac. (See links below)
iPhone apps work on iOS devices (iPhone, iPad or iPod Touch) they will not work on a Mac running Mac OS X 10.7 (Lion) or any other Mac OS X version
Legally Mac OS X can only be installed on computers made by Apple. Some people have had success installing it on other computers.
I have a Mac OS X but I know Mac OS is a computer made by the brand/company, Apple.
Mac OS X is supplied with all Macs. Updates can be downloaded with the Mac's Software Update. New versions can be purchased from Apple stores and other retailers. There are no other legitimate sources.
You cannot without erasing your hard drive and installing Mac OS 9 from scratch. Even then Mac OS 9 may not run on modern Mac hardware because Mac OS 9 needs the ROM chip to boot. Modern Mac OS X hardware uses EFI to boot the system instead of a ROM chip to boot. Mac OS X v10.0 - Mac OS X v10.4 support Mac OS 9 applications and can run them, you just need to install the Mac OS 9 compatibility program which can be found on the Mac OS X Install CD.
The second name of Mac OS X v10.4.5 is Mac OS X v10.4 Intel.Mac OS X 10.4 was known as Mac OS X Tiger.
To comply with the legal agreement you agree to when installing Mac OS X the PC needs to have been made by Apple.
The Darwin kernel of Mac OS X is open source, as are many other parts of the OS. (See links below) but Mac OS X itself is not open source and Apple only allows it to run on Apple hardware.