i got a new ACER predator AG3620-UR308 which came with windows 8, so i wanted to run ubuntu 12.04.2 on it as a dual booting. To be honest, i've been doing dual booting for a while now so, i did the right thing. the box came with 2TB HDD. so i made 4 partitions with a raw partition just after the windows installation partition

I always do manual installation so even if ubuntu didn't detect windows 8, it was ok for me. So i created swap area and finished the installation etc....Grub was install on the only drive there which is sda.

After reboot, grub doesn't even come up.So it always boot in windows 8. I did repeat the installation process twice and yield same result. which is weird because this method always works for me so far.Even the laptop am using to write this post is a dual booting windows 7/ mint nadia installed the same way. Is there anything new in windows 8 that i didn't make provision for? Before starting the installation, all i read about was that , windows 8 should be installed first and ubuntu after. I went ahead and disable secure boot from the BIOS and enabled CSM (don't even know what it means) according to Acer custhelp site . I boot from USB and did fdisk -l bellow is the result:

ubuntu@ubuntu:~$ sudo fdisk -l

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't  support GPT. Use GNU Parted.


Disk /dev/sda: 2000.4 GB, 2000398934016 bytes 
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 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: 0x8c361cb5

Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1  3907029167  1953514583+  ee  GPT
Partition 1 does not start on physical sector boundary.

Disk /dev/sdb: 8178 MB, 8178892800 bytes
255 heads, 63 sectors/track, 994 cylinders, total 15974400 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: 0x0006a87e

Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048    15972351     7985152    b  W95 FAT32
ubuntu@ubuntu:~$

Can anybody shed some light? thank you in advance

EDIT Hey, i just did another trial with 13.04 this time and still no luck.

bios: secure-boot: disabled   
enable CSM : always 

  1-delete previous ubuntu partition and swap area partition.now having free space    
  2- used usb installer to prepare usb with ubuntu-13.04-desktop-amd64.iso   
  3- rebooted : liveusb didnt detect windows 8, used something else   
  4-created partition ext4 for /   
  5-created partition for swap-area   
  6- default grub path is /dev/sda and clicked install

Acer always boots into windows.