1. If there is a previous owner or user that may have the password ask them. This is by far the best as some of the options below may have other consequences.
2. Try leaving the password blank
3. The password is Case Sensitive
Check Caps Lock and try several of Capital combinations
4. How to Log On to Windows XP If You Forget Your Password or Your Password Expire
If you do not have a Password Recovery Disk, it is too late to make it
5. Log in to any account that has Administrator access
Then go to User Accounts in Control Panel
Select the user and change the password
6. Windows XP Pro
At the log-in screen, press Ctrl/Alt/Del twice quickl
Type "Administrator" and leave password blank
Windows XP Home
Reboot, tapping F8 each second
Select Safe Mode at the menu
Select Administrator, leave password blank
Then go to User Accounts in Control Panel
Select the user and change the password
If you are using Windows XP Pro and have encrypted data, you may permanently lose access to the encrypted data
7. Or remove the hard drive and insert the hard drive in another computer. From there you can read the data. It may be necessary to Take Ownership to regain access to the data
8. Another option is to install Windows XP on another partition and take Ownership of your data
You could also perform another installation on the same partition, although this is not a permanent fix and it is recommended to perform a Clean Installation after retrieving your data
9. As a last resort you can perform a Clean Installation of Windows
After this is resolved, take precautions to not lose the password
