If you reset your password using a password reset disk, there are no risks. If you use an administrator account to reset a password for another user, that user will lose access to their encrypted files, encrypted e‑mail messages, and stored passwords for websites or network resources. If the user doesn't have any of these things, or doesn't mind losing them, then using an administrator account to reset a password is a fast and easy way to recover from a forgotten password.
Resetting a password is not the same as changing it. Changing your password doesn't pose any risk. For more information, see Change your Windows password.
For more information about resetting a password, see Reset your Windows password.