I made a boot-repair from terminal, and set the pre installed windows 8 to sda2, and afterwards when I start ubuntu the screen looked funny, and then I used recovery from the start, and now every time I boot ubuntu it's comes whit shell where I can type in user name and password, and my problem is what to type in at the shell root so I can use ubuntu again, I also tried an USB stick whit ubuntu but still can come to ubuntu.
Thanks.
It seems that you are going into shell by default now. You need to reboot, press Shift for a second, then select advanced recovery mode. After that, go to root user and enter the command below:
Then enter the new password for root and type the command below:
Desktop window will work again.