The easiest way I found to install windows on a ubuntu or any linux only pc is as follows -
Download and Extract the entire Windows ISO to any of your drive partition. Just make sure it's preferably an NTFS partition and is not the target partition in which you want to install windows and also...
Then, what is it useful for? I cannot attach a new drive, it has no USB and no optical drive.
I cannot start other systems.Space is not a problem, I can free it