You need to increase the time on your Windows 2008 trial license.
Occasionally you need to bring up a new server before you’ve got all the necessary licensing taken care of; and if something goes wrong with the license purchase, you can run into an issue where a machine that recently became mission critical for someone else is threatening to turn itself off if you don’t plug in a license key. But there is a way to give yourself some extra time to get everything in order.
Log on to the server in question and open a console (I use PowerShell but it should work from cmd as well).
Run the following:
C:> slmgr.vbs /rearm
This tells Windows to reset it’s licensing state, essentially giving you another 30 days; you just need to reboot the machine for this to take effect. Supposedly you can even do this 2 more times if your retailer and/or accounts payable department are being especially annoying but I’ve never put that to the test.