You probably already know that Microsoft released a 90-day trial version of Windows 7 Enterprise, which is a full version without any function limitation. After the trial period, you can re-arm the version to another 90 days (so you can use the trial version for a total of 180 days) by taking the following steps:
1. Start->All Programs->Accessories
2. Right-click Command Prompt, then choose Run as administrator
3. Type in slmgr -rearm, then hit Enter
4. Reboot your computer
5. Reactivate Windows 7 to get another 90 days of trial
Have fun!
