I am sure we all have noticed Microsoft product marketing strategy. Whenever they launch any new product line,there are various flavors of it available right from day one. Some are given adjectives like UPGRADE version or FULL, others RETAIL v/s OEM and then of-course we have various categories of the product like HOME, PRO , SERVER , ADVANCED SERVER etc etc. Well ever wondered what you bought is same as what was advertised ? How to tell the difference. Here comes the help. Look for a file called Setupp.ini that is present on your Windows XP CD and double click on it and browse its content. There is a field called PID=. This PID is what would tell us exactly what we have got.First 5 bytes of PID decide whether (it is OEM or RETAIL or is an UPGRADE ) and last three digits determine what kind of CD KEY will it accept. [b]Here are some of the typical PID values: Retail = 51882 335 Volume License = 51883 270 OEM = 82503 OEM [/b]