Drive letter on Parbreastion is gone

My daughter just called me from out of town and said that her folders are all empty in Outlook Express. She is missing all her incoming, sent mail.

She is sure that it was fine yesterday Dec 23,2004.

So I told her (she is using windows xp,) to use Restore to yesterday.

She tried that and it came up that it could not restore the Virtual F drive because it was stopped from being on the Restore option.

So she Restore still to the 23rd of Dec. and still her Messages are gone.

I then asked her to try the 22nd and she did that with same result. It always said it could not restore F drive but otherwise restored successfully.

Yet - again her messages are not there.

I have 2 questions, Because I never had problems with Restore myself. HOW can 1 drive be "stopped" from being on the Restore file? How can you stop or "un-stop" it ? Where?

She did a Virus check with NOD32 and finds no viruses. She did a Search and Destroy and finds no problems there.

What do you think happened? I am at this time clueless.