Are you absolutely sure she didn't set it up with a Microsoft account or an email address? It's the default setting when setting up a Surface for the first time. You can try the Microsoft account password reset tool with her regular email address, just in case.
You may want to check her SkyDrive/OneDrive to see if she synced up her local files to the internet. If she joined her Surface to a home group, she may be able to get into her files from another Windows 7/8 machine in the same home group, depending on where they were saved, before resetting the machine.
As per Microsoft, if you used a Local account and forgot the password, you must wipe the Surface back to factory settings. Doing a "refresh" does not wipe the password. You can do this without logging into the machine, but you will lose all of the files.
Instructions on a reset/return to factory settings from Microsoft for the Surface (RT, Pro, 2, Pro 2):
- From the Windows sign-in screen, tap or click the Power icon Power icon in the lower right corner of the sign-in screen.
- Press and hold the Shift key. (If you're using the on-screen keyboard, tap or click the Shift key.)
- While the Shift key is still pressed , tap or click Restart. If you get the prompt Restart anyway, tap or click Restart anyway. After Surface restarts, the Choose an option screen will display.
- Tap or click Troubleshoot.
- Tap or click Reset your PC. Surface restarts and the Surface logo displays while Windows prepares to reset your Surface.
- On the Reset your PC screen, tap or click Next.
- Choose either Just remove my files or Fully clean the drive. The option to clean the drive is
more secure, but takes much longer. For example, if you are recycling your Surface, you should choose to clean the drive. If you are keeping your Surface, you just need to remove your files.
- Tap or click Reset. Surface restarts and the Surface logo displays while the reset process completes (this can take several minutes).