Temporarily Bypass Windows Server 2008 and Windows Vista Activation
In Windows Server 2008 (and previous Microsoft operating systems) you must activate your computer in order to use it legally. You have 30 days after installing Windows to activate it online or by telephone If this 30-day period expires before you complete activation, Windows will stop working. If this happens, you won't be able to create new files or save changes to existing ones. You can regain full use of your computer by activating your copy of Windows. Activation is mandatory (unless of course you have a different sort of licensing in your organization).
Last evening, while giving a demo to one of my classes, I started up a virtual machine running Windows Server 2008 RC1. The VM had been installed a few weeks ago and hasn't been used since then, but before it was shut down, I had it configured with a static IP address, default gateway, and DNS server. When the machine was last configured, it was on my office network, thus, the network settings that had been applied to it fitted my office network setup. Thing is that now I needed it, and I needed it at a different location, one that had a DHCP on it. Because of that booting the machine with the current network configuration caused the virtual machine to not be able to access the Internet. All this is good and well, hadn't it been just in time for the Windows Activation pop-up to appear!
If you chose to automatically activate Windows online when you set up your computer, automatic activation begins trying to activate your copy of Windows three days after you log on for the first time. But if you haven't done so, you're stuck with the manually activation process.

The same goes for Vista:
Is there any way to bypass the activation screen and gain access to the system's settings? All I want to do is to change the TCP/IP settings so I can activate the server online. There must be a way!
Hold on! What about one of the oldest tricks in the book? Will that work?
Sure enough, I was able to bypass the activation prompt as easily as logging on (and no, Safe Mode does not work!). I am not sure this is a bug, I don't think it is. It would more likely to believe that somehow the programmers behind the activation process simply ignored, forgot, or where not knowledgeable of this method.
As promised, here is a description on how to do it yourself.
First, get your hands on a time-bombed Windows Server 2008 or Vista machine. Such a machine won't let you log on and use your computer unless you first activate it.
Disclaimer: This article is not intended to be used as a hack/crack or as a way to bypass the legal activation process required by the EULA. The only reason for this article is to help those of you that are stuck, like I was, without the ability to activate their legally owned copy of Windows because of some wrong configuration setting. This article is not a hacking guide, nor is it to be used as an encouragement to use your operating system in ways that are not covered by the EULA. You should only use legally bought copies of Windows (or of any software for that matter). What you do with this information is not my business, and I cannot be held responsible for any legal results that may occur if you so chose to follow the steps outlined here. To make myself absolutely clear – Buy a legal license, activate your copy of Windows, and always use a legally owned product ID.
Next, turn on the computer, and then log on at the CTRL-ALT-DEL screen. You will be prompted to activate your computer. Since I assume you cannot do that because of (for example) wrong network settings, you will probably want to change these settings. So, read on.
Click on the What is activation help link. Instantly, a Help window opens up on the right hand side, telling you about what activation is.
You will also be prompted with a window asking me If you want to use online resources for your help search. Clicked Yes (it doesn't really matter for this demonstration). Next, type CMD in the help search box, and press Enter.
Oh yes. Do you get it now? It's that easy!!!
Amazingly enough, the search results are not blocked in Windows Server 2008 and Vista. Click on one of the first results – Open a command prompt window.
Next, in the help result click on the link to open a Command Prompt window, and behold:
So now you can easily type taskmgr in the command prompt window, and as seen in the screen shot, you can go anywhere from here, including to your desktop by typing explorer in the Task Manager application:
You can work on this computer for as long as you want, change your network settings, grab files or just play a game or surf the Internet - as long as you don't close the activation screen.
Yes, all this also works for Windows Server 2008!
To make myself clear once again - This article is not intended to be used as a hack/crack or as a way to bypass the legal activation process required by the EULA. You should only use legally bought copies of Windows. Buy a legal license, activate your copy of Windows, and always use a legally owned product ID.
Feel free to send me your feedback, I will do my best to reply in a timely fashion. Also, take a moment to look at my other articles on the www.petri.co.il web site.