You can try some of the steps from this link - IT recommends 2 different free softwares you can try. I have used the PC Login Now one. It basically will just blank out the password on an account (can do this for the admin account) so when you go to sign in, just type in the username and leave password field blank. The only downside to this software is it will make you do a checkdisk after you restart because it makes Win7 think there is an issue with the hard drive. After doing the check disk though, it is fine and doesnt ask to do it again. I have seen other tools that you can download for free that will basically crack all the user account passwords on the pc in case you have forgotten one. If you google windows 7 password recover tool you should be able to find others if you do not want to try the ones on the below article.

How to recover windows 7 password
(If by root password you mean a BIOS password on the laptop before it boots to windows, unplug the laptop, take out its battery, and then take out the CMOS battery. This will reset the BIOS to defaults and remove any password protection from the BIOS)