One ntfs partition of my laptop was suddenly wiped out without any notice to me, when I rebooted from Windows 7 to Ubuntu 12.04 today. I am in need of help to save my files on that partition, which are important and unfortunately haven't been backed up yet.

My laptop has two operating systems: Windows 7 and Ubuntu 12.04. with a ntfs partition shared between the two operating systems for storing some data files (109GB, about 97%of which has been used).

I have almost always been using Ubuntu, but today I happened to have to work under Windows. Following is a record of what happened in the time order, numbering according to which operating system I was in at each stage.

1. When I started into Windows 7, right before being able to log in, it took a while and two reboots to configure the Windows. I thought it was normal, since last time when I was using Windows two weeks ago, it took very long and several reboots to update Windows, since the last time I used Windows before then was in November last year.

   Then after finally being able to log in Windows 7, I installed Libre Office, MathType (I got it from http://dl.portablesoft.org/down/?id=2515, which I originally thought was a trial version, but later I learned was a cracked version and felt wrong. I made a copy of it at dropbox http://dl.dropbox.com/u/13029929/MathType_6.8_PortableSoft.rar, not for distributing it but to list it there just in case it will help to identify the problem), and MikTex. I then edited some .doc files in the ntfs partition under both Microsoft Office with MathType, and Libre Office.

2. When I finished working under Windows and rebooted into Ubuntu, Ubuntu did some filesystem checking and reported that the ntfs partition was not able to be mounted.

3. Then I rebooted again into Windows, and found that

   • the ntfs partition had been emptied, i.e. all the data files were gone, and only one system file bootsqm.dat and one system directory System Volume Information were there, with their last updated time being the time when I first rebooted from Windows to Ubuntu (in fact, it is 4 hours in advanced than the actual time of that rebooting , see immediately below)

   • Also I noticed that the time shown by Windows is not correct for my time zone (UTC-05:00) Eastern Time (US & Canada)), which is 4 hours in advance than the correct time (my current time is 3am, but the computer shows 7am).

4. Same things happened when I rebooted into Ubuntu again:

   • the ntfs has been emptied and left with only one Windows system file bootsqm.dat and one Windows system directory System Volume Information.

   • the time shown by Ubuntu is 4 hours in advance than the correct time.

I wonder what I can do to retrieve my data files back on the ntfs partition?

If I am not able to do it myself, will some professionals be able to help me out?

Thanks a lot!

PS: I didn't think I did any thing that required emptying that partition. But there were quite some works I did during that stage right before the reboot from Windows to Ubuntu when the problem occured. Did I make any mis-operation?