One of the first things that you will want to check is how many days you have left on your trial. To do this you will need to Right Click on Computer and then choose Properties. If you then scroll down the window you can see how many days you have left on your trial.

Trial Version Days Left
Now for the next step you will need to Click on the Start Menu and then Search for Command Prompt. You will then want to Right Click on Command Prompt and choose Run As Administrator.

Run As Administrator

Run As Administrator
Now you will just have to input this simple command: slmgr -rearm
After you run this command you will get a little window that pops up. From here you will want to Restart your system.

Command Completed
After you run this command you will get a little window that pops up. From here you will want to Restart your system.

Command Completed
After you Restart you will want to make sure that the hack actually worked by just Right Clicking on Computer and selecting Properties. This should now show that you have 30 Days Left. So now you may be thinking why can you only use this for 120 Days and not just be able to keep doing this over and over again. Well the thing is that Microsoft limits the use of that code to only be used 3 times so if you do the math that is a total of 120 days. Usually you would want to wait until around the last day to use this hack so that you can get the most days possible out of it.
The Original post can be found here: http://www.howtogeek.com/howto/windows-7/extend-the-windows-7-trial-from-30-to-120-days/
The Original post can be found here: http://www.howtogeek.com/howto/windows-7/extend-the-windows-7-trial-from-30-to-120-days/