If you can remember the username you used, you could try going to the Windows/Microsoft log-in page from a different computer, where you will be asked for username and password.
The log-in screen may have a note saying something like "Forgotten your password? Click here" and when you select that, it takes you to a page where you can ask for a new password to be sent to the email address you gave when you started the Windows account.
If you can't remember your username either, or the email address you gave, or if there is no opportunity to have them send you a new password, then I don't know what you can do.