virtualbox.org

Hi,
hope this is not a trivial question... I'm not a programmer, but need to use a Linux VM for a project.
I have installed, on Windows 7, VirtualBox(4.2.18) with a Ubuntu VM which was already set up (by another group). Now, I need to install Guest Additions because the VM screen is too small.
I read instructions and tips found in the forum, but as my laptop (Asus Ux31E) has no CD/DVD drive, I could not follow them.

Can you help?

Well this is the first time I have answered a question on here, so here goes.
You do not need an actual cd/dvd drive. just add a virtual drive to the vm. Then choose the option to install the guest additions.
It takes a bit to get your head around the virtual world.
Alan

The problem is that the lapdop does not have any CD/DVD physical device ... how can I trick Ubuntu to act as if there was one?

Why would that be a problem? Do you understand the meaning of the word "virtual" ? Tricking the guest into thinking that hardware exists when it doesn't is pretty much an exact definition.

Run your VM and choose "Insert Guest Additions" from the "Devices" menu at the top of the Windows. Don't worry about how it works, it just does. See the user manual for detailed instructions on installing the guest additions in a Linux guest.