This is a suggestion for you as you say you know the correct password.
http://support.microsoft.com/kb/940765
***If you cannot log on to Windows 7 or Windows Vista, you can use the Windows Vista System Restore feature, or the Windows 7 System Restore feature.***You may be unable to log on to Windows Vista or Windows 7 in the following scenarios:
- Scenario 1: You recently set a new password for the protected administrator account. However, you do not remember the password.
- Scenario 2: You type the correct logon password. However, Windows Vista or Windows 7 does not accept the password because the system is corrupted.
- Scenario 3: You delete a protected administrator account. Now, you cannot log on to another administrator account.
- Scenario 4: You change a protected administrator account to a standard user account. Now, you cannot log on to another administrator account.
Make your own System Repair Disk from the information in this Tutorial:
"How to Create a Windows 7 System Repair Disc"
http://www.sevenforums.com/tutorials/2083-system-repair-disc-create.html
Note
AS you are unable to use your Windows 7 to create a Windows 7 System Repair Disc, then you could create it on another computer to use on your computer."
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