Factory reset, from the microKEY Owner's Manual:
If you turn on the power while holding down the OCTAVE DOWN button and OCTAVE UP button, the sett ings of the microKEY will return to their factory-set default values, and the power LED will light up. The process of restoring the factory sett ings will take several seconds after you turn on the power. You must not turn off the power during this time.
Link to manuals and other info is here:
https://www.korg.com/us/support/download/product/0/151/
Here's some advice from Korg, for a different device, but the principle will be the same, and the same drivers are used across a wide range of Korg products:
Disconnect the SV1, then navigate to your main hard drive (usually CSmile [C:], open the Program Files (x86) folder, then the KORG folder, then the KORG USB-MIDI Driver folder. There you should find UnInstDrv.exe. Please run this, click “Next,” and you should see a list of MIDI entries that can be uninstalled. Check every one of the ones that mentions your SV1, then click “Next” again. Click “OK” to confirm.
Then, go to the Start menu, type “regedit”, and press Enter.
Open HKEY_LOCAL_MACHINE, then SOFTWARE, then Microsoft, then Windows NT, then Drivers32.
You should see midi1, midi2, midi3, etc. Please delete all these entries.
Next, reconnect the SV1, and run the “Install KORG USB-MIDI Device” utility to install the SV1 again.
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