I had that twice when I first got Win 10. To fix it, I did a "hard shutdown". That is, hold the power button down until the machine shuts off, then reboot.
Dafydd.
Yesterday windows 10 worked great. This morning the start menu does not work and I have no task bar.I get nothing if I right or left click. As far as I know there was no update involved.At 85 I am not very tech savvy, so if there is a fix, please don't send me to the registry or anything else that is hidden. I had no problems with 10 until today

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