On Windows XP Home, the Administrator account, by default, has a blank password (although some manufacturers assign one at the factory). If you boot into Safe Mode, you may be able to log in as Administrator using a blank password, and change her password while logged in as Administrator from within the Control Panel.
Windows XP Professional machines may or may not have an Administrator password, depending mainly on the OEM's policies. Some leave it blank, others assign the password "password," and others actually assign a real password. In the last few years, though, I've encountered more blank passwords than anything else on OEM installs, probably because they don't want users calling them to find out what the password is.
As Troy and Lance said, there are plenty of password-reset tools out there, but you have to be careful, as it's very easy to plant malicious code in bootable utilities.
If you know someone with a copy of Winternals ERD 2005 (I'm not sure about the 2007 version), it includes a utility called NT Locksmith. Unfortunately, M$ bought Winternals in 2006, immediately pulled the freestanding version of Locksmith from the Web site, and stopped selling the Winternals software altogether after the 2007 release.
There are ISO copies of ERD floating around BitTorrent and eMule, but I would advise against booting into anything downloaded from a P2P network.
There is, however, a ridiculously inexpensive utility called Spotmau Power Suite that is surprisingly useful and feature-packed, considering it's modest price. Among other utilities, it includes a password-reset tool. In fact, earlier today, I successfully used Spotmau to reset a password when ERD failed, because Spotmau recognized the machine's RAID array when ERD didn't. Pretty cool, especially considering that Spotmau costs about 1/20th of what Winternals used to cost before M$ killed it.
One caution: No matter how you reset the password, if your daughter encrypted her files, they will be unreadable if the password is reset from outside her account.
Rich
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