OEM is the version that the brand computer comes with. Although the software may make some minor adjustments to meet the hardware, at least the

brand's hardware (computer) can be used.
In fact, many times, not only the brand computers are available, but the assembly machines are also used. . . .
OEM: It is for computer manufacturers to sell with the computer, that is, the random version.
There are usually three versions of Microsoft's operating system. These three versions are only different from the sales target, and they are

all used in the same way.
kind.
(a) Retail. (Retail version): The one with the beautiful packaging seen in Huacai. Can be upgraded and installed
Fresh installation.
(b) OEM. (random version): only random devices can be shipped, not retail, so it is called random version. Only fresh installation
You cannot upgrade from an old system. If you buy a laptop or brand computer, there will be a random version of the software
Pieces. The packaging is not as exquisite as the retail version, and usually has only one CD and instructions (authorization).
(c) Upgrade: The package is the same as the retail version, but the price is much cheaper. Only upgrade installation,
For a fresh installation, the installer will check the old system CD, and you can install it after checking.