Black screen enter password

Which operating system ?
Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer
Windows Advanced Options Menu

Please select an option:
Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Enable Boot Logging
Enable VGA mode

Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode
Start Windows Normally
Reboot
Return to OS Choices Menu

Use the up and down arrow keys to move the highlight to your choice
select safe mode with command prompt

Click start run type cmd press Enter
black screen should open DOS mode
this will vary depending on your operating system

type in net user username
For eg. If you want to change administrator password , type net user Administrator

It will prompt you to enter the new password.
Enter the new password and the password is changed

or

Click "Start," then select "Run." In the text box displayed, enter "control userpasswords2" and press "Enter." This opens a configuration window.

Click the user for whom you want to disable the password login.
After selecting the user, remove the check mark labeled "Users must enter a username and password to use this computer."

Click "Apply."

A dialog box will prompt you for the password.
Enter the user's password to authorize the changes and press "OK."

Reboot your Windows XP computer.
When it shows the list of user profiles, click the user whose password was disabled.

You should be able to log in without a password.

Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer
Windows Advanced Options Menu

Please select an option:
Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Enable Boot Logging
Enable VGA mode

Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode
Start Windows Normally
Reboot
Return to OS Choices Menu

Use the up and down arrow keys to move the highlight to your choice
select safe mode with command prompt

Click start run type cmd press Enter
black screen should open DOS mode
this will vary depending on your operating system

type in net user username
For eg. If you want to change administrator password , type net user Administrator

It will prompt you to enter the new password.
Enter the new password and the password is changed

or

Click "Start," then select "Run." In the text box displayed, enter "control userpasswords2" and press "Enter." This opens a configuration window.

Click the user for whom you want to disable the password login.
After selecting the user, remove the check mark labeled "Users must enter a username and password to use this computer."

Click "Apply."

A dialog box will prompt you for the password.
Enter the user's password to authorize the changes and press "OK."

Reboot your Windows XP computer.
When it shows the list of user profiles, click the user whose password was disabled.

You should be able to log in without a password.
also

Click the "Start" button.
Double-click "User Accounts."
Select the user account you wish to change.
Select "Change My Password."

If you wish to remove the password, select "Remove My Password."
also

Click start control panel Open User Accounts in Control Panel. On the Users tab, click the name of the user whose password you want to change, and then click Reset Password.

Just click In New password and Confirm new password, type the new password by just clicking, and then click OK.

Notes You can change passwords only for local computer accounts, such as guest, administrator, or accounts you create for your computer.

You cannot change your network logon password in User Accounts.
To change your own password, press CTRL ALT DELETE and then click Change Password

Which operating system ????.....
Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer
Windows Advanced Options Menu
Please select an option:
Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Enable Boot Logging
Enable VGA mode
Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode
Start Windows Normally
Reboot
Return to OS Choices Menu
Use the up and down arrow keys to move the highlight to your choice
select safe mode with command prompt
Click start run type cmd press Enter
black screen should open DOS mode
this will vary depending on your operating system
type in net user username
For eg. If you want to change administrator password , type net user Administrator
It will prompt you to enter the new password.
Enter the new password and the password is changed
http://wiki.ljackson.us/Control_Userpasswords2
if this fails you will need to
Select safe mode with networking to download
you could download all of these or just one save them to a usb drive for later use if one fails to remove the password
Windows Password Recovery Basic
http://majorgeeks.com/CmosPwd_d239.html
A CMOS BIOS password recovery tool
Editors note: This tool should only be used by experienced computer users.

Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer
Windows Advanced Options Menu
Please select an option:
Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Enable Boot Logging
Enable VGA mode
Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode
Start Windows Normally
Reboot
Return to OS Choices Menu
Use the up and down arrow keys to move the highlight to your choice
select safe mode with command prompt
Click start run type cmd press Enter
black screen should open DOS mode
this will vary depending on your operating system
Click "Start" icon in the lower left corner of your computer screen
Type the word "run" in the window that appears.
A second pop-up window will appear; type in the letters "cmd," then select "OK."
This will bring up the black DOS command screen.
Type next to the administrator account the following command: net(space)user(space) the username(i.e. johnadams) *. After typing this command, hit "ENTER" on your keyboard.
Type in a new password in the command screen prompt that ask you to type a password. Type the new password again once you are asked to confirm.
Type the word "Exit." This will bring you back to your login screen.
Enter the new password that you selected.

Which operating system ? and computer type and model ?
Laptop or Desktop ? HP , ASUS , COMPAQ..........

Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer
Windows Advanced Options Menu
Please select an option:
Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Enable Boot Logging
Enable VGA mode
Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode
Start Windows Normally
Reboot
Return to OS Choices Menu
Use the up and down arrow keys to move the highlight to your choice
select safe mode with command prompt
Click start run type cmd press Enter
black screen should open DOS mode
this will vary depending on your operating system
type in net user username
For eg. If you want to change administrator password , type net user Administrator
It will prompt you to enter the new password.
Enter the new password and the password is changed
http://wiki.ljackson.us/Control_Userpasswords2
if this fails you will need to
Select safe mode with networking to download
you could download all of these or just one save them to a usb drive for later use if one fails to remove the password
Windows Password Recovery Basic
http://majorgeeks.com/CmosPwd_d239.html
A CMOS BIOS password recovery tool
Editors note: This tool should only be used by experienced computer users.
Please see the enclosed read me if you would like to run it from Windows.
Failure to follow instructions (from Windows) will cause your anti-virus to flag this as a virus.

Restart your computer repeatedly tapping the f8 key to enter safe mode while the screen is black once in safe mode where the only things working will be your keyboard and mouse allowing you to attempt to repair your computer Windows Advanced Options Menu Please select an option: Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt Enable Boot Logging
Enable VGA mode
Last Known Good Configuration (your most recent settings that worked)
Directory Services Restore Mode (Windows domain controllers only)
Debugging Mode Start Windows Normally
Reboot
Return to OS Choices Menu Use the up and down arrow keys to move the highlight to your choice select safe mode with command prompt Click start run type cmd press Enter black screen should open DOS mode this will vary depending on your operating system type in net user username For eg. If you want to change administrator password , type net user Administrator It will prompt you to enter the new password. Enter the new password and the password is changed if this fails you will need to Select safe mode with networking to download you could download all of these or just one save them to a usb drive for later use if one fails to remove the password Windows Password Recovery Basic http://majorgeeks.com/CmosPwd_d239.html A CMOS BIOS password recovery tool Editors note: This tool should only be used by experienced computer users. Please see the enclosed read me if you would like to run it from Windows. Failure to follow instructions (from Windows) will cause your anti-virus to flag this as a virus. http://majorgeeks.com/Dr._Freeware_System_Utilities_d6416.html Dr.Freeware System Utilities which includes data recovery software, data backup, password reset tools for Windows helps you to maintain your system. Dr.Freeware is freeware, you can download and use it for free. http://download.cnet.com/lazesoft-recover-my-password/3000-18501_4-10973339.html Lazesoft Recover My Password Home Edition is a very easy to use Windows password recovery freeware

http://download.cnet.com/password-cracker/3000-2092_4-10226556.html password cracker free

Reset 10.5 Leopard & 10.6 Snow Leopard password

1. Power on or restart your Mac.
2. At the chime (or grey screen if your chime is turned off), hold down Command+S on your keyboard to enter single-user mode.
3. Type mount -uw / and press Enter.
4. Type launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist and press Enter.
5. Type ls /Users and press Enter. This lists all of the usernames on the computer - helpful if you don't know or remember what these are.
6. Type dscl . -passwd /Users/username password and replace "username" with one of the users displayed in the previous step. Replace "password" with a new password of your choice. Press Enter.
7. Type reboot and press Enter.

Reset 10.4 Tiger password

1. Power on or restart your Mac.
2. At the chime (or grey screen if your chime is turned off), hold down Command+S on your keyboard to enter single-user mode.
3. Type sh /etc/rc and press Enter/Return.
4. Type passwd username and replace "username" with the short name of the user account for which you'd like to reset the password.
5. Type your desired password and press Enter. It won't show itself on the screen, so be careful what you type. You will most likely have to enter it again to confirm.
6. Type reboot and press Enter.

Hi,

What you can do is turn the computer off and then when you turn the computer on or as soon as you press the power button to turn the computer on start tapping the F8 key repeatedly until you get a black screen that says advance boot menu option .Then used the arrow keys on the keyboard,highlite the option that says safe mode and then hit enter,select the operating system and then when you get the log on screen select administrator .If it takes you to the desktop then go to start?control panel?user accounts11?select ur account and then click on the option that says delete password.Once it is done restart the computer it should take you to the desktop without you putting in the password.

You can also try this :

1. Click Start and Run
2. Type "Control Userpasswords2" and press enter.
3. Uncheck the box for "Users must enter a user name and password to use this computer."
4. Click Apply and Ok.

all the best...

Do you mean you are locked out of your profile/Windows Account? Your password does not work?.

If this is the case, you can keep clicking F8 right after your computer turns on until you get a menu screen on a black background. With the arrow keys on the keyboard select Safe Mode and click enter.

You will get to a more basic (larger) looking Windows screen and there with be an "Administrator" account. If no password was entered for this account, click this account and enter with no passsword. Go to Settings > Control Panel the double Click the icon for User Accounts. Choose your Account and reset/erase or change your password.

Reboot and you should be able to log in with the new password you created or without a password (if you erased it).