If it stopped all at once then the entire planet would be destroyed (probably). That is a lot of inertia. But the bits of you that still existed for a brief period would be very warm, indeed.

If the Earth completely stopped rotating without any of the inertial consequences, it would have a day of about 1 year. There would be a ~6 month period of burning heat, and a ~6 month period of complete darkness and cold. The heat would be like nothing else experienced on the Earth that we know, a hot summer day that lasts 6 months with no respite. If it doesn't cook us then the droughts and wildfires will finish us off. It'll be too hot and dry to grow any of our crops. The cold side will be frozen solid and in darkness for 6 months, also little chance of survival.

If the Earth becomes tidally locked, which means the same side always faces the sun, there is hope. There will be a ring of twilight where temperatures may remain survivable, but the hot side and cold side will be even less survivable. However, the weather as air of vastly different temperature is exchanged between hot and cold sides would probably make it unlivable even if the temperature in the twilight zone is livable.