1. Boot to the Ubuntu CD you just created.
2.When asked, click Try Ubuntu
3. Install the software: From the menus in the top right corner of the screen, select System, Administration, Software Sources. Check the two options not yet checked: Community-Maintained Open Source Software (universe) and Software restricted by copy-right or legal issues (multiverse). Click close then reload. After the program is done procession, select System, Administration, Synaptic Package Manager from the menus in the top right corner.
4. In the resulting windows search field, enter chntpw. A program with that name should appear in the list. Click it and select Mark for installation. Click the apply toolbar icon. Click apply, and wait until the installation is complete.
5. Now mount the drive, from the top menus, select places, then your internal hard drive or Windows partition. When it is mounted, a File Browser window will appear. Double click the folder icons to go to the Windows drives Windows\System32\config folder. Leave this window up. From the top menus, select Applications, Accessories, Terminal.
6. Arrange the two windows so that you can see the top section of the file browser window behind the terminal window. In the Terminal command line window, type cd /media/ and the path to your config folder, using the folder names at the top as a guide. The press enter. Now type sudo chntpw -u logon SAM, where logon is the log on name for the administrator account. Press enter, the last section of scrolled-up text will begin …User Edit Menu. Press 1, the enter. At the resulting question press Y. When the program is done, click the power button logo in the upper right corner and reboot into windows….
Article credits: PCWORLD Lincoln Spector