unable to mount usb hard drive

 I lent my Maxtor 400Gb usb hard drive to a friend who runs windows and needed to transfer his data to a new laptop that runs Vista. After he finished he deleted his data and returned it to me. The drive that used to mount automatically now tells me it cannot be mounted due to unclean shutdown. The message says 'mount is denied because ntfs is marked as still in use. Help really needed please.
 if I run sudo fdisl -l I get

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x33f233f1

   Device Boot Start End Blocks Id System
/dev/sda1 * 1 19269 154778211 83 Linux
/dev/sda2 19270 19457 1510110 5 Extended
/dev/sda5 19270 19457 1510078+ 82 Linux swap / Solaris

Disk /dev/sdb: 400.0 GB, 400088457216 bytes
255 heads, 63 sectors/track, 48641 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x55207314

   Device Boot Start End Blocks Id System
/dev/sdc1 1
 I'm hoping somebody can help, there's some data I really need to access.
Ian