I have been duplicating servers at work in preparation for testing upgrades. The virtualized environment lives in a completely isolated network, and it will only exist long enough to test some major upgrades.

Most of the servers p2v’d without asking for activation, but on the last server I was not so lucky.

When server 2008 demands activation, you either have to activate or it logs you out. Thankfully, I stumbled across this article:

http://www.petri.co.il/bypass-windows-server-2008-activation.htm

Essentially, you tell it to try activating (which fails, because there is no internet), then you select other options, and click on the “What is Activation” help link at the bottom. When the help window pops up, you search for “cmd”, and select the help article for Opening a command prompt. This will let you open a command prompt, where you can then type “explorer” and you will get your start menu and desktop, etc.

At this point, you could configure the network, and complete activation if you were so inclined. I was not.

Server 2008 (and Vista and Windows 7 and Server 2008 R2) normally provides a 60-day “grace period” for activation. This grace period can be extended by “rearming” windows activation up to three times. Most literature on the internet states that this allows you a 240-day trial period. What they don’t mention is that you can also rearm a machine that has “lost” its activation well beyond 240 days after installation.

Follow the directions here:

http://support.microsoft.com/kb/948472

That is,
Open an elevated command prompt, and run “slmgr.vbs -rearm”. After a bit you should get a pop up telling you that it succeeded.
Note: because this must be run from an elevated command prompt, you still need to start explorer first.

Hope this helps save you some time!