Hello, im trying to dual boot(not wbui) install ubuntu alongside my windows 7. When i boot from the cd and start the installation i dont get that option, i only get to point to /dev/sda (and i cant click on anything but install). when i click install i get "no root file system is defined please correct this from the partitioning menu". i've read that all you have to do is point to / but it already is.

any help would be great.

Please start into the live mode, launch a terminal, type in the command (lower case L, not the number 1) and post the output here, so that we get information about the partitions on your machine.

There's usually an option to do custom/manual partition setup.

Here it is:

ubuntu@ubuntu:~$ sudo fdisk -l

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 / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x1549f232

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 1929185279 964489216 7 HPFS/NTFS/exFAT
/dev/sda3 1929187328 1953122303 11967488 7 HPFS/NTFS/exFAT

i know, i thought so too, but the option isn't there.

OK, Linux can see your partitions, which means that your disk is not a dynamical volume (which is a good thing). I would recommend to start Windows 7 and use the Windows Partition Manager to shrink your system partition (the one which is about 1TB in size) about the amount you want to spend for Ubuntu. Don't create new partitions. Then start the Linux installation again and look if there is an option to use the free space.

OKay, i will try this. but do i leave this new partition as unallocated, and then boot back into ubuntu? also, i've read that you can only have
4 partitions. right now, it says i have 3. and linux also needs 3 (boot partition, root partition, and swap).

You can have a maximum of 3 primary partitions (which you already have) and 1 extended partition (the one you'll create during install). The latter can contain different logical partitions which will be mounted as /, /boot, etc..

so i unallocated 100G, and i tried installing again but i still get the same thing: "no root file system is defined please correct this from the partitioning menu". Do i have to use gparted and make that 100G into a
ext4 format?

You should get an option that you want to use the free space during the installation process. Please start the CD into Live-mode, start the installer from there and provide screenshots from the state were it fails and the steps you made immediately before the error message.

it looks exactly like this: http://www.youtube.com/watch?v=l5cTNg0gs7A&noredirect=1
no matter what mode i choose. (btw thats not me)

wow just getting linux running is stressful! im thinking of buying a 2nd hard drive for linux, but i've read
it may give me the same error. i guess its my computer. its only a year old and it doesnt even have usb boot...

This is weird. Please post your exact hardware specs. Also, I would give the alternate install CD a try, possibly it works with that.

Thank you so much for helping me, i will give you my specs when i get home in 3 hours (i went to my internship).

Btw, i've tried three different linux distros and wubi before ubuntu, they all give me that same error "no file system is defined".