Hi.
Sorry to read about your problems.
A "ordinary" replacement by use of 2.5" could be done if you could manage
to format trhe drive as it should be to operate in the KN.
But that's the big issue, you probably don't find the sofware needed.
Maybe a e-mail to webmaster at this site
http://keysoftservice.ch/index-e.htm can direct you to the developer of the KN Harddrives so you can get it fixed?
Another shot is to remove the harddrive so your KN can be played without this
option, but honestly, I'm not sure if you have to "downgrade" the software in
the KN to make it work, but my guess is that should work without the HD inside.
I'm sure here are some experts reading this who can tell.
Good luck in your hunt for repair or needed software.
GJ