purple screen boot 12.04 (black with recovery mode)

purple screen boot 12.04 (black with recovery mode)

So I have a problem with my asus computer: everything went just fine until
today, my computer shows me the grub menu when I start up like it usually
does. But when I choose a version of linux the only thing I get is a
purple screen or a black one if I use the recovery mode.
I have been using ubuntu 12.04 for about a month and I did not download a
single update the day before it started to act like this. It was also
running perfectly fine on start up until today.
I tried to replace quiet splash with nomodeset but that didn't help,
running an older version of linux didn't help either, as I have the same
problem on every version.
I have an Asus motherboard 8 Gb DDR3 Ram Nvidia GTX 560 graphics card
Intel i7 quad core processor
(Someone posted a similar question here: Ubuntu 12.04.2 LTS boots to
purple screen but nobody answered :/)
Edit Boot repair didn't solve the problem, here is the link it gave me:
http://paste.ubuntu.com/6033493/
Second Edit: ctrl alt delete who worked before the boot repair doesn't
work anymore... :/ (I could use it when I had the purple/black screen)
3th edit: The Grub commandline works, so maybe it's a problem with
graphics? (Even though I didn't change anything when I last used my laptop
on Ubuntu..)