I have two Windows 7 machines in my local network.
One Windows 7 with Virtual Box (running Ubuntu) installed.
Is it possible to connect to the Ubuntu from another machine by using vagrant ?
So essentially you are trying to access/manage a VirtualBox VM on a remote host with Vagrant? Nope, that's not possible currently with the existing Vagrant-VirtualBox provider :( Though there are solutions for other platforms like EC2 https://github.com/mitchellh/vagrant-aws/ that accomplish roughly the same...
In your vagrant file, use a bridged network type then you can access it from another machine. This line for example:
config.vm.network :public_network