You're talking about login onto the machine?

If you used a "user password" and also had an "Administrator" password, the simplest thing to do is to log on as Administrator and create a new user account. Just ignore the old one. The Administrator should be able to access all the files the old username had, and copy/move them to the new account.

If you didn't create a password for "Administrator" you may be able to just log in as "Administrator" with just a blank password.

Passwords in WinXP are stored in BIOS, and are encrypted so that there is no reasonable way to read one out. In the extreme case recovery from a lost password involves shutting down the computer and (usually) removing the battery, and (usually) shorting a couple of pins on the BIOS chip to dump the BIOS memory, then (usually) reloading enough of Windows to create a new Administrator account, followed of course by creating a new username. You will need very specific instructions from your computer manufacturer to get the right pins and procedure, as a "minor slip" can destroy the BIOS chip and/or its program/setup.

It's possible that your computer sat for long enough for the internal battery to run down, which allowed the BIOS memory to dump itself, so the computer no longer remembers the password you used.

If you have your WinXP installation CD, booting from it may let you in to reinstall, as the Administrator password probably also is lost. An "overlay" reinstall of Windows, without reformatting the drive, isn't likely to lose data, but there are no guarantees on that. A "normal" install of Windows usually does reformat by default, so you'll have to intercept the default to tell it not to format.

Vague maybe, but I'm on a quick trip home from the WVA fest, and can't do lookups now.

John