How can I unlock my computer montior log on screen ..My Windows XP screen shows a small window that says ...this computer is locked and only >>>>> (I) can unlock it...but I can't ...help. I don't know what you mean..''please enter a valid product''..It's my computer screen.

Setting a password on Windows 7/Vista/XP can add a level of security to your computer. So you are often advised to set a password on Windows. In addition, it is highly recommended to change Windows password regularly. And it is a good habit to keep your PC security by changing Windows password. Here are some simple methods to change Windows password among Windows7/Vista/XP.

Method 1: Change Windows password by using Control Panel.

The steps to change Windows password have a little different on different Windows systems. The following steps are based on changing Windows 7 password.

1. Click Start, Control Panel and User Accounts in order.
2. Pick the specified Windows account whose password you want to change.
3. Click on change my password.
4. Enter your current password and type a new password, and then click Change Password button.
Note: you may need appropriate privileges to change the password of another user.

Method 2: Change Windows password by pressing Ctrl +Alt +Del.

It is the easiest way to change Windows password for Windows 7, Windows XP and Windows Vista.

1. Press Ctrl + Alt + Del when you log onto your Windows XP/7/Vista PC.
2. Click on Change password.
3. Type your new password, type your new password to confirm it, and then press Enter.
Note:
1. If your press Ctrl+ Alt +Del when you log onto your Windows XP, it will show you the classic security options instead. Click Change Password to change Windows XP password of the logged on user.
2. If the security options does not appear. Task Manager shows up instead of the security options. Just go to Start, Control Panel, User Accounts and Change the way Users Log on or off. And then uncheck Use the Welcome Screen.

Method 3: Use lusrmgr.msc to change Windows 7/Vista/XP password.

The following steps are operated to change Windows Vista password.
1. Click Start button and input lusrmgr.msc into the Search box.
2. In the coming Local Users and Groups screen, double-click Local Users and Groups, and then click Users.
3.Right-click the account that you need to reset the password for, and then click Set Password.
4. Type and confirm the new password.

Method 4: Change Windows password with Windows Password Unlocker

Windows Password Unlocker Standard allows you to change lost or forgotten password on Windows 7/Vista/XP.You can adopt this method to reset Windows password when you are locked out of computer without a password reset disk.
1. Download and install Windows Password Unlocker Standard in any accessible computer.
2. Run the program and insert a bootable CD/DVD or USB flash drive.
3. Burn an ISO image file to the CD/DVD or USB flash drive.
4. Set your locked computer to boot form CD/DVD or USB drive.
5. Change Windows password with the burned CD/DVD or USB drive

These are the simple methods can be applied to change Windows password on Windows 7/Vista/ XP. Of course, there are some other ways for your choice. Please remember your changed password. It is often for one to forget Windows password after changing it. Otherwise, you'll need to bypass lost Windows password with Method 4 if you are locked out of computer.