Android OS on a Pc

What are you looking to do with it?

If you are trying to develop, there are custom virtual dev environments available from Google.
If you want to use it as an OS on x86 hardware look here. It's kind of sketchy.
Or pick up like a Jetway Arm based motherboard.

Even then, I'd still recommend like a Fedora distro.
No, you can't install Android on generic PC hardware.

There are projects in various stages to add Android compatibility to other OSs. Things like Bluestacks run Android in a VM environment and performance can be poor.

Android-x86 isn't sketchy, but it is very buggy and has limited hardware support.
I ran Android on my old Asus 1005HA netbook. It ran ok, but I didn't really care for it.
Bluestacks is kinda nice, I checked it out yesterday and got several games installed and running pretty good. Tales of Honor: The Secret Fleet I had on my phone and it ran fine in Bluestacks until the game dev borked something with a patch yesterday.