Check IME Language and Input Method Settings:
Manage the input and display language settings in Windows
Reset IME:
Right click on the Language Bar or click the Options button at the bottom right corner of the Language Bar.
Select Settings
Select the desired IME from the Default input language list in the Text Services a Input Languages window.
Make sure Google IME is disabled.
If required reinstall the Japanese language pack.
Make sure Windows is updated.
Open Command Prompt as Admin and copy-paste the following 2 commands one after the other followed by hitting the Enter key:
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow