Question: My house has 2 bedrooms, a living room and a studio (Room for a computer, shelves, etc., don't know how it's called in the US), each one with a RJ-45 connection (LAN, Internet). I want to install speakers in the living room and that they could accept input from every one of the rooms. How can this be done?

Answer: 
<http://opensource-sidh.blogspot.co.uk/2011/06/recover-grub-live-ubuntu-cd.html> works perfectly, with very clear instructions!
Ensure that the ISO is mounted on the VM; if it is, then it should appear in the results when you do 'ls' at the grub rescue prompt, and you should be able to continue with step 4 as normal.

That said, it may be simpler just to rebuild the VM from a fresh Ubuntu install, and recover your files from there. If you go that route, I'd suggest cloning a safe copy the new VM as soon as you've finished the stock Ubuntu install, or else right before you recover your data; that way, if the VM crashes and dies again, you can just clone the safe copy and start from there, rather than having to rebuild from scratch again.