Sometimes you are forced to use Windows just for some seconds to get the work done. Fortunately MS was kind enough to release a Trial Windows image that you can run legally for 90 days as explained here (in Portuguese) : https://acassis.wordpress.com/2013/02/27/baixando-e-rodando-uma-imagem-do-windows-no-virtualbox/
But my laptop is old and its resolution is only 1366×768 and this resolution doesn’t appear as an option in the emulated Windows on VirtualBox. Even in the advanced options this resolution is not present.
After some search in the Internet I discovered how to create new resolutions option on VirtualBox:
$ VBoxManage setextradata "IE9 - Win7" CustomVideoMode1 1366x768x32