I'm about to buy a new fast computer for downstairs, but my upstairs computer is very old and slow. So, I want to build one new fast computer downstairs, then somehow link it to my monitor upstairs. Then run 2 different operating systems on that one computer, and have it send the second operating system to my upstairs monitor so that it seems like I have my own computer upstairs. But how do I do this?? I understand how to setup software like "virtualBox" on my actual physical downstairs computer, but no tutorials explain any further than that.