That expired in August, so it won't run if you try to install it now.
If, on the other hand, what you have is the Release Candidate (RC), that doesn't expire until next summer, although your computer will start shutting down every two hours from 1st March 2010.
Make sure you have a valid installation key - Microsoft stopped issuing those some time ago, and if you don't have an unused one you can't install the RC.
Should I upgrade to Windows 10? 8 reasons why you should upgrade to Windows 10... and 2 why you…