I’m using Oracle’s VirtualBox on Ubuntu to host a Windows7 OS running a huge .net application that uses a specialized bit of usb hardware. Oddly this all works pretty well, modulo any program droppage of usb hardware. This has to be manually reattached to the VM (mouse clicking) when this happens. All of this is free except the Windows7 copy, and it needs to be a fully licenced copy, unburdened of a particular pc.