There's not much to do other than to re-load Windows.
I doubt very much that you'd get alot of help (if any) in resetting your password, because we have no way of knowing whether you're legit, or are pretending to have lost your password so as to harvest help in hacking into a computer that does not belong to you.
I'm sure you'll understand...
And when you do get your system back, be sure to this time choose a password that you can't forget, and then top also create a password hint to help you should you forget again.
Thanks for your prompt reply . I am not into hacking etc as i am not that smart . I have tried the following steps i got by googling
ØReboot the Windows Vista and boot up with Windows Vista installation DVD.
ØWhile the Windows Vista installation interface pops up, click the Repair You Computer link at the bottom-left corner.
ØNext, the System Recovery Options dialog box appears.
ØSelect Command Prompt
ØIn the Vista Command Prompt, type mmc.exe and press ENTER key to bring up the Microsoft Management Console.
ØClick on the File menu, select Add / Remove Snap-in option, locate and select the Local Users and Groups on the left panel, and click Add button to add it to the right panel.
ØNow, the Choose Target Machine dialog box pop up. Keep the default setting by clicking the Finish button – that means using the Local Users and Groups snap-in to manage this local computer, and not another computer in network.
ØClick OK button and return to MMC windows. Under the Root Console in left panel, double-click Local Users and Group that was added earlier. Click on User folder, locate and right-click the target Vista logon account that found in the right panel ( in this case Administrator ) . Select the Set Password from the right-click menu to set a new password / reset old password .
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However , the MMC option does not seem to work , as it says "class not registered" . Would request you to be kind enough in not taking away this thread or ban my IP address as i am doing a research on this for quite some time now. Please let others share their knowledge . We are not into stealing data or breaking systems .