Try one or both of these:

If you're being asked for a username and password, try this:

Go to Control Panel => User Accounts => Change the way users log on or
off => check the 'Use the Welcome screen box'.

If it's having to click a name in the Welcome screen, try this:

Go to Start => Run and type in "control userpasswords" {without the
quotes, and there's a space after "Control"}

Uncheck the box "Users must enter a user name and password to use this
computer".

Note: The default password for the built in Windows Administrator account is
normally blank (none).
Use this hidden/admin account to fix your problem.

For XP Home users:
Boot the computer into Safe Mode
Do this by pressing the F8 key after the Power On Self Test is finished,
until the Start menu appears.
This will get you to the correct menu window.
Once in Safe Mode, you will see the normally hidden Administrator account
and any other accounts.
(Note: Accounts are displayed alphabetically).
Use the Up/down arrow keys to highlight the 'Administrator'  account;
Remember as mentioned above: The default password is a blank (no password
required).

Also See: Forgotten your Windows XP Home password
http://support.microsoft.com/kb/894902/en-us
and: http://support.microsoft.com/kb/894901/

For XP Pro users:
You do not need to go into Safe Mode.
At the Welcome Screen, do/press the Ctrl-Alt-Del keys twice to display the
Windows logon box.
Type in "Administrator" (without the quotes) and 'if' you assigned a
password when you set up Windows, then enter it. (Note: by default the
password is blank, no password need be entered)

Once your in, then:
Click Start/Run/and type in: Control Userpasswords2 and then press OK
Next click on the Advanced tab and then click Manage Passwords.

Also:
Download Tweak UI from Microsoft
http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx
Then expand the Logon option and select Autologon and Check the Autologon
box.

OR

Start/Run and enter: CONTROL USERPASSWORDS2
On the User tab: pick (highlight) the account you want to automatically log
on
Then uncheck: Users must enter username and password
Next click Apply and enter the password (if the account you pick has a
password)
Finally click OK until your completely out

Finally:
How to turn on automatic logon in Windows XP
http://support.microsoft.com/kb/315231

JS

(and Becca later adds...)
"Becca" <Becca@discussions.microsoft.com> wrote in message
news:C3351E10-C7F2-4426-8C97-4230503887A0@microsoft.com...

Becca:
If the responses from Patrick and others to your query haven't resolved your
problem, let me suggest the following...

Obviously you have access to another computer so you can access the
internet, right? If so, go to the following website...
http://home.eunet.no/pnordahl/ntpasswd/

1. On the top of the webpage click on the "Bootdisk" button.
2. In the "Download" section of that page click on the cd070927.zip file and
download it to your Desktop. Note it's a ZIP file so the contents of that
file will have to be extracted.
3. I assume you know how to do this by merely right-clicking on the ZIP
file, click on Extract All, Next, Next, Finish.
4. A folder will be created on your Desktop titled "cd070927".
5. Inside that folder will be the cd070927.iso file. It's this .iso file
that allows you to create a bootable CD from that .iso image.
6. Hopefully, you have a CD-burning program, e.g., Nero, Roxio, etc., that
allows you to merely double-click on the .iso file and the program will open
and create a bootable CD from that .iso image. If you don't have such a
program perhaps you have a friend or acquaintance who does and he or she can
help you with creating the bootable CD. There are other programs available
on the net that allow you to do this as well but these third-party programs
that I've mentioned make it a very simple & straightforward process.

Now that you've created the bootable CD that's designed to reset your
password, insert the CD in your optical drive and boot to it.

The following are step-by-step instructions for using the program. The
example involved is a single-partitioned HDD, but the basic steps are the
same for any size HDD, except where the drive is multi-partitioned. If the
latter is the case the steps will be slightly different but they will not be
unduly complicated or substantially different under those circumstances.

As you progress through the screens the information provided and steps
involved look more complicated than they really are. In virtually every step
during the process you, as the user, will simply be pressing the Enter key
or some other simple keystroke. So please don't be unduly concerned as you
look through the following. Relax, and take your time during the process,
OK?

1. Hopefully your PC is set up so that it will boot to a bootable CD. If
it's not, change the motherboard's BIOS boot priority setting so that the
CD-ROM is first in boot priority.

2. Boot to the password reset CD. At the first screen you will see the
"boot:" prompt. Press Enter.

3. The next prompt ("Step ONE") will be "Select: [1]". Press Enter.

4. The next prompt ("Step TWO") will be "What is the path to the registry
directory? (relative to windows disk)
[WINDOWS/system32/config]:". Again, press Enter.

5. The next prompt will follow text "Select which part of registry to load,
use ..." and list three options. The default prompt will reflect the first
option ("Password reset ..."), indicating "[1]". Again, press Enter.

6. The next prompt at "Step THREE" will indicate "What to do? [1]". Again,
press Enter.

7. A bunch of information will follow with the final line displaying the
prompt, "or simply enter the username to change [Administrator]". Type your
user name, e.g., BECCA, and press Enter. Ensure you've correctly entered
your user name in the proper case (uppercase or lowercase as you have
originally set it).

8. More information will follow ending with the following prompt...
"Please enter new password:". Type an * (asterisk or star) and press Enter.

9. The next prompt will be...
"Do you really wish to change it? (y/n) [n]". Type y and press Enter.
(You'll receive the confirmation "Changed!")

10. The last line of the following prompt will read...
"or simply enter the username to change [Administrator]". Type !
(exclamation point) and press Enter.

11. The last line of the next prompt will read...
"What to do? [1]" . Type q and press Enter.

12. The next prompt ("Step FOUR") will read...
"About to write file(s) back! Do it? [n]". Type y and press Enter.

13. At this point you should get the "EDIT COMPLETE" message with the
following prompt...
"You can try again if it somehow failed, or you selected wrong New run? [n]"
Just press Enter.

14. The final prompt will be a "#" signaling that the program has finished
its work. Remove the CD from your optical drive and reboot.

Hopefully your Administrator's password has been reset to a blank password
and you should gain access to your system.
Anna