partitioning - problem installing ubuntu 14.04

I want to install Ubuntu 14.04 on a system with Windows 8 already installed. I do not get the option of "install beside windows". It shows that all of my drive is free space and unpartitioned whereas in Disk application I can see my partitions.

sudo fdisk -l result:

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors

Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xd087a632

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      718847      358400    7  HPFS/NTFS/exFAT
/dev/sda2          718848   409602047   204441600    7  HPFS/NTFS/exFAT
/dev/sda3       409602048  1748721663   669559808    7  HPFS/NTFS/exFAT


Disk /dev/sdb: 8054 MB, 8054112256 bytes
256 heads, 29 sectors/track, 2118 cylinders, total 15730688 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: 0xc3072e18

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        4184    15730687     7863252    c  W95 FAT32 (LBA)