On this one as OEM are only supposed to be sold with a built system or if the buyer accepts responsibility as a System Builder and is prepared to support the product in that case Windows.
I haven't heard of MS allowing this practice to continue and while they once did provide genuine software to those who brought in [b]Good Faith[/b] and helped them track down the Pirates they stopped doing that over 2 years ago. So I wouldn't be holding my breath waiting.
Now the way that OEM Windows should come is in a shrink wrapped bag with the COA stuck on the outside of the plastic which you have to peel off and fix to the case. On the rare occasions when I do use OEM product I always stick it on after I've loaded the system as I find the COA hard to read once fitted to the case.
There should also be a bit more of the sticker left on the plastic above the COA after you peel the COA off. If there was nothing at all stuck to the plastic you most likely have a pirate copy or even worse a genuine copy where the person/business has hard loaded HDD and then applied the COA's to the different cases but they should have supplied the install CD with the systems.
MS is currently in the process of cracking down on all the cases of cheap MS product being offered on the net I'm not sure what they are doing about E-Bay sales.
Best of luck
Col ]:)