I captured your screen grab and marked what looks to be multiple devices, I'm guessing you finally had one to many USB devices loaded for the Akai and Windows finally became confused and for some reason has kept one loaded.
One thing to try, with the keyboard plugged in go into Device manager double click on the device in "sound, video & game controllers" go to the drivers tab and "uninstall" if the device show as still present, delete it as well.
Unplug the keyboard, shut the computer OFF, in a couple of minutes boot the machine, wit until it settles then plug the keyboard in. Try and always use the same USB port.
Also... have you installed any other USB devices before your keyboard stopped working.. you have -a lot- of USB devices listed.
If all elses fails registry editing would be the next step.