Three tips to reset admin password without data lost:
Tip 1. Reset Windows 7 password with CMD
1. Logon you laptop with another user account which has admin privileges.
2. Click Start, type in "CMD.EXE" in the search box, press Enter.
3. Command screen apears, type in "net user" "user name" " new password", press Enter.
The user account password will be replace as the new one.
Tip 2. Reset Windows 7 Password with Repair CD
1.Boot the machine with your Windows 7 Repair CD.
2.Select "Repair Mode".
3.Use "System Restore" to set Windows back to a point before you changed the password.
4.Log on with your old password.
5.Plan ahead a little and create, test and document a spare admin account, same as you have a spare house key for emergencies.
If you have no reset disk, this is a better way for you.
Tip 3. Recover Windows 7 admin and user password with USB Load a program which can recover lost password for Windows 7 on another PC, burn it to a bootable CD/USB flash drive. Boot your locked computer from the USB, then you can recover any user account password. Read more if you'd like: How to recover Windows 7 password.