Server 2008: how to check and reset the evaluation period

To check the time that is left on your current evaluation period, run the Slmgr.vbs script that is in the System32 folder. Use the -dli switch to run this script. The slmgr.vbs -dli command displays the number of days that are left in the current 60-day evaluation period.

To reset the evaluation period, type slmgr.vbs –rearm, and then press ENTER.
Restart the computer.