I have a laptop running Windows XP SP3 with one internal hard drive partitioned into C: (system), D: (storage) and I have an external hard drive, F: (external drive). Yesterday the machine was running fine. Today, I go back to it and see that it's just showing a blinking cursor. Checked through the BIOS and the hard drive checked out fine. CTRL-ALT-DELETED the machine a few times, but I was never able to boot back into the operating system. I threw in a live CD and found out that the boot order of the drives has changed. The external drive is now C:, the system partiton is D:, and the storage partition is E:.

Does anyone have any idea of how or why this would have occured? Auto system updates are turned off so there should have been no automatic reboot of the system overnight, and anti-virius runs on the machine and has found no infections before this occured.

Edit When I was looking through the BIOS of the machine, I did see that the boot order was changed. But still the same question remains, what would have caused this to happen? I can't believe that a random reboot happened and totally changed my hard drive setup.