If you can not find the password you must reset the password. You just google related keywords like "windows password unlocker" , there will be a lot of related result on Internet. As far as I know, the most popular method as followings :
1. Login to a computer that can link to Internet. Download Windows Password Unlocker 4.0 and decompress it on that PC. Note that: there is a .ISO file. Burn the .ISO file to a CD.
2 Get out the newly created CD and insert it to the locked computer.
3 re-booted the locked computer and then followed the process of instructions. Just a few steps, the old password was removed.'''
4 Setting new password:
Step one: Open the "Control Panel"
Step two: Click the "User Account "
Step three: Select the account you wanna to set a new password.
Step four: Click "changing Account " and "set up password", then fill out the form as listed. Click "Create Password".