How to change the product key for Windows Server 2003 R2

You need an OEM media, that's actually a different media from retail and VLK, so you can't use OEM keys on those other ones.

You can try "looking around" for it, IYKWIM; as long as you have a proper license key, it doesn't actually matter where did you get the media.

There are a couple of ways to this. By far the easiest way is just to insert disk 2 of Server 2003 R2 and install it. This will only work if you use the R2 product key, and your 2003 install and R2 disk are the same SKU, so both retail, both OEM, both volume licence etc, which I suspect is what is causing you the issue here.

There are two further options if you do not have the same SKU:

• Run Server 2003 R2 disk 1 and select the upgrade option. This will not work if you have OEM media for R2
• Run a repair install of server 2003 R2

See this Microsoft article for full details.