I had a decommissioned server (Dell PE2950) that we could still use, it had OEM Windows 2003 Std on it but wanted to use it as a new host with VMware ESX5 to put a couple legacy severs on it. I wiped it clean and maxed out the memory. But when I added the memory I noticed the product key sticker was a "WindowsServer08 Std 1-4cpu" product key, and it also had a Virtual Key.

Not sure why it had Win2003 and not Win2008 from the start, but I would like to use that license if I can. The virtual host would stay on the same physical server, so there shouldn't be a problem with licensing... but I do not want to use Hyper-V unless I can not help it. I have installed ESX5 on the server, but I cannot get the Windows 2008 server to activate. The product key is hard to read, and I have checked the key quite a few times.

But my question is... Is it because Hyper-V was not installed on the host? But I thought you could use the product key alone on a virtual host? Maybe because I am not using a Dell Windows 2008 disk but iso from MS directly via the Volumne Licensing site?

EDIT: well, Im pretty sure I got the product key correct. If its not the product key, could the activation problem be because Im not using hyper-v or maybe the correct install dvd?

EDIT2: maybe because I added 28GB of memory? Originally 4GB...