How can I reset Windows 7 pasword

Use the PartedMagic LiveCD (with unetbootin you can also put it on a USB stick), then boot to that and under the extras menu you have an nt password resetting tool:

http://partedmagic.com
http://unetbootin.sourceforge.net

Here are some options
http://www.howtogeek.com/96630/how-to-reset-your-forgotten-windows-password-the-easy-way/

http://windows.microsoft.com/en-US/windows7/Reset-your-Windows-password

http://pcsupport.about.com/od/windows7/ht/reset-password-windows-7.htm

http://www.top-password.com/knowledge/reset-windows-7-password.html

would any of these suggestions help?
http://pcsupport.about.com/od/windows7/ht/reset-password-windows-7.htm
step-by-step instructions...

Please check my article
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/A_9832-Recover-lost-administrator-password-in-windows-2008.html

http://pogostick.net/~pnh/ntpasswd/bootdisk.html
works great. There are instructions towards the bottom of that page to make a bootable USB stick.

Boot it up and use option 4 to enable the Administrator account, then blank that account's password.

Boot into windows, choose the Administrator account (password blank) and logon.
From the User Accounts applet in Control Panel, reset the password on the account you want to use, and set a new password for the Administrator account.

Before rebooting, disable the Administrator account again:
click the 'start' orb
type cmd in the search box
hold down Ctrl+Shift and hit Enter (or right-click the result that appears at the top of the start menu in the Programs section, and choose Run as administrator).
click Yes on the UAC dialog
In the Administrator window that opens, run the command
net user administrator /active:no

"The command completed successfully" should appear.

Reboot and you should be now able to logon the other account (on which you reset the password in User Accounts).