Como assim no meio do Ubuntu..!? Você tem acesso a partição do Windows..?
Poste o resultado de ==> sudo fdisk -l novamente..!
ubuntu@ubuntu:~$ sudo fdisk -l
Disk /dev/sda: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders, total 1250263728 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x98000000
Device Boot Start End Blocks Id System
/dev/sda1 63 262142 131040 de Dell Utility
/dev/sda2 * 262144 16293393 8015625 7 HPFS/NTFS/exFAT
/dev/sda3 25946110 859633875 416843883 5 Extended
/dev/sda4 16293888 25944063 4825088 83 Linux
/dev/sda5 25946112 236144639 105099264 82 Linux swap / Solaris
/dev/sda6 625266688 859633875 117183594 83 Linux
/dev/sda7 236146688 625264639 194558976 7 HPFS/NTFS/exFAT
Partition table entries are not in disk order