intel драйвер suppressed after removing Nvidia card (switching from Nvidia to Intel failed)

today, my Nvidia graphics card gave up. I переместите it from my computer and switched to the on-board one:

$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)

I have two systems on this computer: One is Kubuntu 15.04 which used the nouveau драйвер, before (and never used the proprietary nvidia драйвер). The other one is в Kubuntu 15.10 which used the proprietary nvidia-352 драйвер before.

After the removal of the Nvidia драйвер, my Kubuntu 15.04 booted without any trouble and X works умер with two monitors attached and with all 3D effects. I really do not need an Nvidia card.

However, the Kubuntu 15.10 does not work properly. First, X didn't start at all. So I logged in to the text я утешил (which was fortunately working я умер) and I uninstalled all nvidia драйвер stuff:

$ apt-get purge nvidia-*

After this, I rebooted and the system still didn't work :-( I found out that the problem was в wrong 'xorg.conf'. It stated (among other things):

Section "ServerLayout"
    Identifier "layout" 
    Screen 0 "nvidia"   
    Inactive "intel"
EndSection

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID "PCI:0@0:2:0"
    Option "AccelMethod" "None"
EndSection

I переместите the 'Невключите "intel"' line, changed the "nvidia" to "intel" and invoked startx => got в graphical system. I rebooted and the file was wrong again.

After some digging, I found that I have to pass 'nogpumanager' to the kernel, hence I edited '/etc/default/grub', ran 'update-grub' and rebooted => the system booted умер.

However, I saw that some of the desktop effects - e.g. the cube - don't work (they work умер in my Kubuntu 15.04).

The problem seems to be that X используй the 'modesetting' драйвер instead of the 'intel' драйвер. I tried to explicitly set 'Драйвер "intel"' in my 'xorg.conf', but then X does not start :-(

When I run 'Xorg - я конфигурировал', however, it lists 'intel' эксперт the first line under 'List of видео драйверы: '!

I assume that my previous installation of the nvidia proprietary драйвер somehow somewhere forced the intel драйвер out of the way. However, even after hours of searching, I still didn't find where this problem is located.

In which file does it suppress the intel драйвер?!

Please help! I really don't want to re-install the system, just because the nvidia драйвер left some garbage behind (that I was unable to find, so far). And I really would like to использовал the cube and many other 3D effects again ;-) They seem to be automatically suppressed when using XRender (instead of OpenGL). And I seem not to be able to enable OpenGL when not using the proper драйвер, even though 'glxinfв says:

$ glxinfo | grep OpenGL
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.6, 256 bits)
OpenGL version string: 3.0 Mesa 11.0.2
OpenGL shading language version string: 1.30
OpenGL context flags: (none)

Also, тест programs like 'glxgears' work умер (and even say, I had 2500 + FPS).

Best regards, Рама :-)