Configuring CentOS 7, ParaView and Oracle VM VirtualBox on Windows 7

I am attempting to run OpenFOAM 2.3.1 on an installation of CentOS 7, running inside a virtual machine hosted by Oracle VM VirtualBox on a Windows 7 machine. I am not trying to use any remote tunneling, SSH etc, it is all local. The exercise is proving disastrous. startx starts bringing up the gnome interface, with the 'first time install' window. However in the virtual machine, the GUI ignores all input and effectively all I can do is kill and restart the VM. Not even Ctrl+Alt+F2 etc will switch to other terminals. With Paraview or xhost or anything else on the command line no matter what I export the DISPLAY variable as, the result is: xhost: unable to open display "localhost:0.0" or xhost: unable to open display or whatever $DISPLAY returns. What I would like to know is effectively what are the ways in which the system could be broken, what exactly to look for in the stack of technologies as evidence of faults, where any settings are stored, and what things may well be the key to getting this working. - Machine operating system: Windows 7 Professional - Virtual machine manager: Oracle VM VirtualBox Manager 5.2.18 - Virtualised operating system: CentOS 7 3.10.0-862.14.4.el7.x86_64 - OpenFOAM version: 2.3.1 **Update 1:** It turns out, xterm was not installed. I have run yum install xterm on an attempt to run xinit. There is a new behaviour, a GUI window with only xterm visible. Again, no input is being accepted. I will now have to restart the machine. **Update 2:** Attempting to reinstall VBoxLinuxAdditions.run the kernel build reveals "ERROR: Kernel configuration is invalid."