Make sure to read all info before performing the task in full.
If you ever forget your password to log onto Windows this site's tool is very helpful:
Offline NT Password and Registry Editor
You first need to click on "Bootdisk" in the top left corner to download the tool. Then use a burning program to burn the iso that is found after unzipping/unraring the downloaded file, to a CD. I used PowerISO, which can be downloaded here, to burn the iso(image) to a CD.
You then need to put the newly created CD into the PC of which you forgot the password to. You may have to change the boot order in the BIOS to boot from the CD drive first, unless you are given an option to choose your boot device when your computer starts. Now, just boot from the CD and follow the instructions from the page where the tool was downloaded from.