So I have installed Ubuntu to use as a server and recently found that I had quite an issue at hand with no idea how to fix it. My max resolution available was 800 x 600 and this isnt really useful when the windows you are working with are larger then the screen you can see.
One fix to this is press the ALT key on your keyboard and click the mouse, while the mouse is clicked you can drag it around and the screen will move with the mouse.
But I wanted to get my screen resolution fixed so off to google I went.
I found that in some situation if you have a KVM in place Ubuntu wont read the max screen resolution of you monitor and will default to a max of 800 x 600.
To fix this you will need to modify the /etc/X11/xorg.conf file. Here are the suggested contents for a xorg.conf file:
Section “Screen”
Identifier “KVM Screen”
Monitor “KVM Host Monitor”
EndSection
Section “Monitor”
Identifier “KVM Host Monitor”
HorizSync 30-70
VertRefresh 50-75
# ‘man xorg.conf’ says you can set the pixel clock in KHz.
# This is an UNTESTED example for 10-110 MHz clock:
#Option “MinClock” “10000”
#Option “MaxClock” “110000”
EndSection
Make sure to replace the HorizSync and VertRefresh ranges with your monitor’s actual capabilities. You can really mess up your monitor if you try to drive it with refresh rates that it can not handle.
one way to modify this xorg.conf file is to use:
sudo gedit /etc/X11/xorg.con
Please let me know if this has helped you.
I am not an expert with Ubuntu or Linux. Your questions are better suited in a forum the here. I am just sharing my experiences so others may find the info needed to help them fix an issue with their system.