I use the lates ubuntu version. Till to day I use it with an acer trravelmate4070 and an LG screen in order to expand my destkop. Works great. Till today that I desided to connect my LG screen to a KVM switch in order to share the big screen with an other pc when I need it. In the KVM switch the resolution is lower and I can not manually change it. I read many solutions about making an .conf file but since I am new to Ubuntu I am afraid , more over I realized that these articles talk for the same problem but not as an expantion screen but as a main screen. Any idea how to config correct this file? I send the links of these articles here:

http://robert.penz.name/219/workarou...-kvm-switches/

Where is the X.org config file? How do I configure X there?

Thank you!