I have purchased windows 7 . The seller didnt provide me the Certificate of Authenticity (COA) , When i asked him he says its a digital copy ordered via Microsoft volume licensing , In this case i just want to know whether is it true or not . How do i verify whether my windows is GENUINE or not . P.S (I validated via genuine advantage tool and it passed good)

Let me guess... EBay? It is not valid without a Certificate of Authenticity. Microsoft's own words: "...without it, you will not have a legal license to run Microsoft software." http://www.microsoft.com/howtotell/content.aspx?pg=coa -Noel

here's a possible explanation: Question about the COA?

The only valid online store from which to buy an electronic copy of Windows is Microsoft's own store, hosted through Digital River. The terminology "The seller" implies otherwise. -Noel

only? did you read that on that page you linked that says you must have a COA sticker?

If your seller received his license by "volume licensing", he can't sell that. The cheaper price for this distribution channel is a result of the amount of licenses acquired at a time by enterprises, government, educational institutions, etc. It is not meant and allowed for reselling to "end customers" (the only exceptions are, f.e., that an university permits the use of a volume-licensed copy to some teachers or students for their homework). Usually, a volume license doesn't even include physical media like discs, it's a key only that must be activated against special activation servers (KMS) or by using a MAK (multiple activation key). Both are not available for individuals, and in both cases there isn't a supplementary COA key because there aren't media that could have a "sticker". To put it short: You may have passed the WGA check (did you try online checking?) but the whole thing has a certain smell."I think there is a world market for maybe five computers. (Thomas J. Watson, Sr.)

only? did you read that on that page you linked that says you must have a COA sticker? No, it was stated in a discussion on this site some time ago. -Noel