I am trying to install ubuntu 14.2.16 on VirtualBox. It has installed correctly, but I was having a problem related to window size. It is not possible for me to switch ubuntu in full screen mode. I got some solution for that i.e. installing Guest Additions. But afterwords I got error: unable to mount C:program files/oracle/VirtualBox/GuestAssitions.iso For that i got one solution.(Unable to mount the CD/DVD image on the machine Sandbox) I followed all steps given by but as it says about VBoxLinuxAdditions.run file, it should be executable. But file I am having in my host PC is not executable. I even checked settings in file property, its type is program still not executable, its opening in text editor.
What should I do now? Even if anybody could suggest me different solution for switching it in full screen it would be really helpful.