I've been using ntfs-3g, trouble free under linux (Ubuntu Intrepid) for quite a while now, until today when I've booted into Windows and it no longer reads the disk as NTFS and no FS is listed under disk management. The EXT3 and Swap partitions under windows show as Health (Primary Partition)

The disk configuration is as follows


[---736GB NTFS---] [--187 GB EXT3 / --] [ 7.96GB Swap ]

in that order.

If you can see the NTFS partition from Linux then see http://ntfs-3g.org/support.html#mbr