I downloaded the security fixes on windows update today. I'm still on SP1 of XP Pro.
Now it takes me straight to the "login" screen which I had set to bypass the username and password prior to the update.
I can't remember my login info, or at least what I thought it was isn't working.
I tried booting in safe mode to try to get to "system restore" but the login screen came up even in safe mode.
I'm using my kids computer to send this. Help please!!!!

Try starting your Windows with "Safe Mode with Command Prompt" option. IF you get command prompt(cmd), write(without quotes):

"control userpasswords2"

Again, if you get to Windows 2000-style User Accounts application:
On the Users tab, clear the "Users Must Enter A User Name And Password To Use This Computer" check box and then click OK.
In the Automatically Log On dialog box that appears, type the user name and password for the account you want to be logged on each time you start your computer.

OR
If above does not help you,
this is a utility to (re)set the password of any user that has a valid (local) account on your NT system, by modifying the crypted password in the registrys SAM file. You do not need to know the old password to set a new one.

It works offline, that is, you have to shutdown your computer and boot off a floppydisk.

Ask your friend or use your kids computer to download the utility and make this floppy.

Another site and utilites:
http://www.petri.co.il/forgot_administrator_password.htm