There are numerous ways to reset passwords. The most obvious way is to reinstall everything to factory state. There are less extreme ways, though, and they could work for you. What you need is a program that resets passwords. Many of these are free. I have never used one, but it is my understanding that they work. Even if you got one that doesn't work, that doesn't mean that another won't do the job.
You can try some free software to like Ophcrack, ftspassword which can help reset windows password, but not sure.
Also some paid software like iSeepassword would be the first choice.
it works but not free.