From what I remember seeing the last time I was looking for information about their USB-MIDI drivers, it seems that Casio's older drivers had some sort of compatibility issue with Windows 10, and that they've apparently never made a point to update those drivers. That would be fine if their newer drivers worked with all of their models, but it seems that the drivers which are compatible with Windows 10 do not work with their older models.
I no longer have my old Casio, so I'm not able to try it out with my Windows 10 computer to see if I can find a driver that works with it, or figure out some way to get an old driver to work. I'll see if I can borrow my old Casio back from my sister-in-law, or ask my sister if her son's Casio is somewhere that's not too difficult to get to.
That is a kind thought.
My interest in the Casio LK-300TV has been reawakened by my granddaughter wanting to imitate a gorilla playing the Elton John song "I'm Still Standing"
I've managed to convert a very good downloaded midi file using the SMF Converter that converts midi to CM2 format that is one of the formats supported by the Casio LK-300TV; however, some of the midi files available are not as good or convert as well the "I'm Still Standing" file, I thought it would be a more efficient method to use a direct connection with the Casio.
I have just loaded a win7 64bit driver from the Casio site CCUSBX64_INST and it seems to be working. No errors reported in device manager and sound is output from the Casio LK-300TV to the PC.
I cannot see the Casio card slot or anything else on the Casio LK-300TV, perhaps that is asking too much?