[Nvidia] VAIO Z690, Ubuntu won't reach login screen

I think Ubuntu failed to launch graphic server, and used terminal as a "workaround".
Login/password should be what you defined at installation, else try ubuntu/<nothing>.
When you get screen with five dots, could you press <ESC> and report last messages.

As instructed I pressed escape when the Ubuntu (five dots) come up. Something flashes on the screen before ending up at the terminal login. Unfortunately it's just up for a microsecond. Is there any way to pause or freeze so I can read what it says?

speech-dispatcher disabled; edit /etc/default/speech-dispatcher
* Pulseaudio configured for per-user sessions saned disabled; edit /etc/default/saned
*Enabling additional executable binary formats binfmt-support fsck from util-linux-ng 2.17.2
/dev/dsa5: clean, 136829/10510336 files, 1465878/42016512 block
*Starting AppArmor profiles
Skipping profile in /etc/apparmor.d/disable: usr.gin.firefox
*Setting sensors limits

Forget about dual boot. Try virtualization. It has some advantages:

* No need for maintaining a xomplex boot loader and boot setup.
* No silent data corruption e.g. of NTFS volumes.
* No Windows installation on bare hardware which an become infected or otherwise corrupt.
* A virtual instance of Windows in a VM like VirtualBox can be created, spawned, reset/destroyed and deleted at any time!
* Run multiple clones of your VM and return to a state in the past.
* Do low-level tracing with strace, ftrace, or other tools "below" the VM and figure out things you cannot otherwise.
* Share VMs across mutiple loactions and systems (depending on hardware constraints).
* Todays VMs ike Virtualbox, Paralells (whatever), etc. bring graphic accelleration (D3D/DirectX) or at least OpenGl with them which coms in handy with for e.g. playing Games, Animation (Maya, Blender) or stuff like CAD.
* A VM gives you the power to run different versions of on OS.
...

Disadvantage(s):

* It takes some considerable amount of processing power without hardware virtualization. e.g. Virtualbox on a 10.000 MIPS machine K7 generation runing Windows XP is not so much fun (depending on what applications you run inside that specific VM). 30-40GIPS are recommended without built in CPU hardware virtualization. check with »cat /proc/cpuinfo«.

* An OS run in a VM is limited in its executions depending very much on the underlyng operating system and the quality of the VM solution in use. I recommend to make some test cases and check whether the VM is sufficient or not.

* An OS instalation within a VM containment is oftern stored within its own formats using "special" data structures. Most VMs offer convertion methods however. Although this is not a problem most of the time and in most use cases I tell you to consider this wehen moving OS installations out of or into a VM.

It seems you have a big issue, probably with graphic card as usual.
When you boot, could you select recovery mode and change back Nvidia driver, to confirm issue is linked to Nvidia.
I think that at startup launch of graphic server fails.

Unfortunately I do not have the powers to change the state of this question to SOLVED, EXPIRED or INVALID. Someone here at Launchpad either grant me that permission or simply apply the change in state to this question, please.