Windows – Is it worth buying a Windows 7 upgrade package or should I buy a OEM copy

Quoted from this thread Windows 7 licensing rights:

What license do you have? Retail, OEM, and Volume Licensing are all different.

Volume Licensing http://windowsteamblog.com/blogs/springboard/archive/2009/08/06/windows-7-enterprise-edition-understanding-software-assurance-volume-licensing.aspx:

"Virtual OS Rights - Use up to four instances of Windows in virtual OS environments for each license that has active Software Assurance coverage." Notice that this appears under MDOP. "MDOP is an add-on subscription license"

You can find the retail and OEM EULAs here: http://www.microsoft.com/about/legal/useterms/default.aspx

As far as I know, since the days of Vista, Microsoft allowed running up to 4 virtual machines, as long as they use the same operating system and serial number as in the physical machine.

EDIT

It's finally quite unclear what are the virtualization rights of a desktop Windows version, with conflicting opinions between authorities (even Microsoft). Finally, only a thorough examination of the EULA can maybe give some answer (and maybe not).

It will install, but the problem is it will reject the key. An OEM key requires an OEM disk, and retail requires a retail disk.

You did not post what model or brand of laptop, so it is hard to be more specific with the following advice: First, I would call the manufacturer and see if I could buy a replacement disk (about $20 typically because you are not buying a license, just the media). That is a good idea long-term.

In the short term, you want to get up and running, so see if you have a friend with an OEM disk even if it is not from your manufacturer. I have used the Dell restore disks on non-Dell systems before. The main difference is that if I were installing it on a Dell system, it won't ask me for the key or to activate, but it does on a non-Dell system. This is not a problem for you since you can just put in you key that is on the sticker.