When I went to log on to my server 2008 environment this morning I realised that the domain administrator password had expired. I forgot to check the ‘Password Never Expires’ checkbox when I setup the machine- oops!
However this blog post really saved my bacon – http://lordoftheping.blogspot.com/2009/05/i-did-not-use-my-tests-virtual-machines.html
It turns out it is really quite easy (worryingly easy in fact) to reset the domain administrator password!
Hope this helps someone