Windows 7 Milestone 1 features Reduced Functionality Mode, same as Windows Vista RTM. With Vista Service Pack 1 , Microsoft scraped the anti-piracy mitigation from the operating system, by going back to the Windows XP state, when dealing with piracy, unactivated or expired copies of the platform.

In contrast, copies of Windows 7 M1 move to reduced functionality mode immediately after the user signs into an account. The reason for this is the expiration of the test-period for Build 6.1 6519. The initial limitations can be hacked easily by allowing Internet Explorer 7 to connect to Microsoft, and then typing “C:“ in the address bar. This will open Windows Explorer which will permit users to access “My Computer” in the Windows Explorer window. Here, right click on the system partition while holding the Shift key pressed and open a Command Prompt window. Just type Explorer and hit Enter in order to bring the user interface to life. Still, be advised that Windows 7 M1 will boot unexpectedly at short periods of time, even with this hack, making the now expired copy of Vista's successor unusable.

Source:→ Softpedia