David;
Try leaving the password blank.
The password is Case Sensitive.
Check Caps Lock and try various of Capital combinations.
http://support.microsoft.com/?kbid=321305
If you do not have a Password Recovery Disk, it is to late to make it.
Or
Log in to any account that has Administrator access.
Then go to User Accounts in Control Panel.
Select the user and change the password.
Reboot to Safe Mode, 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.
Here is another option:
http://www.wininternals.com/products/repairandrecovery/index.asp
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.
After this is resolved, take precautions to not lose the password.
Clean Installation:
Disconnect all peripherals (camera, printer, scanner, etc)
Disconnect network/modem cable.
Go to BIOS and set CDROM as boot device before hard drive.
Insert Windows XP CD and reboot.
At "Press any key to boot to CDROM" quickly press a key and follow the
prompts for a Clean installation:
http://www.winsupersite.com/showcase/windowsxp_sg_clean.asp
Delete all partitions in step 5 if you desire to erase all data on the
hard drive.
Partitioning and formatting will be done automatically.
All data will be destroyed, back-up important data first.
Enable or install firewall BEFORE connecting network cable.
http://support.microsoft.com/?kbid=283673
Install ALL Critical Windows Updates:
Start/All Programs/Windows Update
After you are finished, you will need to load the appropriate drivers.
If your computer was shipped with Windows XP, these procedures may or
may not apply.
Check your manual or contact the computer manufacturer for more
details.