ubuntu 12.04

After login I have a black screen. Clicking the mouse few times brings back my desktop screen and I can only access the programs that I have in desktop. Now I have a message:

Sorry, Ububtu 12.04 has experienced an internal error.

details:
ExecutablePath
     /usr/bin/gnome-control-center
Package
     gnome-control-center 1:3.4.1-0ubuntu1
Problem Type
    Crash

Try logging in to Unity2D session...

I don't have access to terminal. To log out I have to press Ctrl-Alt-Del. Logs out, goes to Log In screem, asks for password and goes black again.

Press CTRL+ALT+F1 and run:

killall -u $USER

Then change the session on the login screen. You can run a terminal by pressing CTRL+ALT+T as well.

Now I have another error: The application Compiz has close unexpectedly. Compiz crashed with SIGSEGV

Looks like is Nvidea problem.

CTRL+ALT+T does not work. After killall it goes back to Login, asks for password and does the same.
Can I go back to 11.10? How?

But at the login page did you change the session?

I don't know what you mean by change the session.

I just disabled NVidea drivers. Made another Login and the apps and the up bar appears very big, but appears. NVidea drivers are not working in 12.04

It's nvidia, not nvidea.

What is the output of:

sudo lshw -C display

You may fid the screen you are using isn't doing what it is supposed to do, making the driver not load properly.

After I disabled Nvidia drivers and restart the computer everything looks normal. No Nvidia driver is active.

result:

description: VGA compatible controller
product: C61[GeForce 6150SE nForce430]
vendor: NVIDIA corp
physical id:d
bus info: pci@000:00:0d.0
version:a2
width: 64 bits
clock 55MHz
capabilities: pm msi vga_controller bus_master cap_list rom
configuration: driver=noveau latency=0

sudo add-apt-repository ppa:ubuntu-x-swat/x-updates; sudo apt-get update; sudo apt-get install nvidia-current; sudo nvidia-xconfig

Then reboot

After doing that I only get one message: Video4 VGA Mode Not Supported . The screen is black.

What video resolution do you use?

I had to uninstall nvidia to work again.

apt-get purge nvidia-current

It only works if there is no nvidia driver installed.

Resolution: 1440 X 900

You may need to manually edit /etc/X11/xor.conf

If you add the below text:

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 280.13 (buildd@rothera) Fri Aug 5 12:28:41 UTC 2011

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 280.13 (<email address hidden>) Wed Jul 27 17:18:55 PDT 2011

Section "ServerLayout"
    Identifier "Layout0"
    Screen 0 "Screen0" 0 0
EndSection

Section "Monitor"
    Identifier "Monitor0"
    VendorName "Unknown"
    ModelName "Plug And Play"
    HorizSync 15.0 - 46.0
    VertRefresh 49.0 - 61.0
    Option "DPMS" "off"
    Option "DPI" "96 x 96"
EndSection

Section "Device"
    Identifier "Device0"
    Driver "nvidia"
    VendorName "NVIDIA Corporation"
    BoardName "GeForce 6150SE"
EndSection

Section "Screen"
    Identifier "Screen0"
    Device "Device0"
    Monitor "Monitor0"
    DefaultDepth 24
    Option "TwinView" "0"
    Option "metamodes" "1440x900_60 +0+0"
    SubSection "Display"
        Depth 24
    EndSubSection
EndSection

Save the new file, close gedit and reboot, it should be ok