Is a windows xp oem an upgrade or full new disk ? ?

Question

and why is the price so cheap because it's an oem

Answer 1

it is a full disk that requires an oem sticker.  The difference between retail and oem is that the oem is meant to be sold with hardware that must remain with the oem cd key that is included whereas, the retail version may be installed on upgraded and modified pc's as you go on through the years.  They both can only be installed on one machine at a time.

Answer 2

Oem is full new disc , not supposed to be sold without hardware to prove it was installed on a new computer. If it is really cheap it is probably pirated but should still work . Of course you are taking your chances.