With regards to the being unable to type your password in the Terminal issue, have you tried just typing your password characters in anyway, and then hitting the Enter key?
You won't see the characters, or asterisks etc. when typing a password in Terminal, you just type the password characters & hit Enter.
It's possible also that the hardware on the "old & knackered" media centre you're trying to install to is past it's use by date & causing issues.
Just because something looks genuine doesn't mean it is.
Printing an official looking sticker and attaching it to a non-official DVD is very easy to do.
As already mentioned in this thread, the contents of the DVD might have been altered, perhaps in such a way that's making the install or correct running of the operating system fail.
EDIT: Too slow I was, what I said's already covered in the post above.
You won't see the characters, or asterisks etc. when typing a password in Terminal, you just type the password characters & hit Enter.
It's possible also that the hardware on the "old & knackered" media centre you're trying to install to is past it's use by date & causing issues.
Just because something looks genuine doesn't mean it is.
Printing an official looking sticker and attaching it to a non-official DVD is very easy to do.
As already mentioned in this thread, the contents of the DVD might have been altered, perhaps in such a way that's making the install or correct running of the operating system fail.
EDIT: Too slow I was, what I said's already covered in the post above.