Looking on Ebay for the most cost effective way to get this Compaq Presario running and legit I see where many sell Product keys along with a useless dead hard drive or some other piece of hardware. It looks like the product key came off of a computer now trashed but the key itself they say has never been used. Apparently these sellers are abiding by Ebay (and apparently Microsoft) policy and there is no shortage of watchers and bidders, so it looks like it is on the up and up. I now have a version of Windows 7 working on this pc but not activated, according to the Ebay claims these product key numbers work? To say the least I'm puzzled, yet curious as how this all works. Microsoft says the way for me to go is purchase Windows 7 for $118 whereas these tech guys on Ebay says a $40 investment in a product key gives me the same thing. appreciate if someone can shed some light on all this, thanks