portable harddisk problem

[manishjha18]

strange but my hard disk(80 gb-Seagate-new) suddenly changed into raw format from ntfs-and all its data are gone-when i do see the properties it shows free space =0,used space=0. i have to reformat it-
i still don't know the reason why it occurred-after clicking on drive it showed the following error----------

--windows delayed write failed
the file or directory is corrupted and unreadable---------------------


is there any way to prevent in future---

[Lucky_star]

http://support.microsoft.com/kb/330174