2017 15 Inch Mac Book Pro fans runs at a very high level and stops responding

At a very basic level, that is a sign of severe overheating which can destroy important components in your computer.

Can you please tell us what activities you are doing when this happens? That is important to getting a better diagnosis in this text-based setting. Example: Video conferencing, so popular since the pandemic, works both the CPU and GPU very hard and is the "COVID Culprit" in many overheating reports. since early 2020.

If you are running useless anti-virus and /or so-called "cleaning" apps, that will cause overheating. So will Google Chrome.

How you position your computer while using it also affects how hot it gets.:

• Running external monitors can increase temps.
• Never cover the keyboard with a keyboard protector. Macbook Pros get some cooling air through the keyboard.
• Never block the sides of the computer with anything soft like a blanket or pillow. The computer must be on a hard, flat surface. That is why Apple calls this class of computer "notebooks," not "laptops." On most 15-inch models, there are critical air intakes on the edge of the bottom plate where it contacts the chassis.
• Some hard cases can block the side vents.
• On all Macbook Pros, the important hot air exhaust is the hinge area. I leave 4-6 inches (100-150mm) clearance between my Macbook Pro and anything else of my desk.

The vent locations I mention are shown here:

Remember that the fans in all Macbook Pros are thermostatically controlled. Sensors on and near critical components tell them to speed up when rising temps are detected. Thus the fans running are an indication that an important safety feature is working.

IF the fans start running at full speed as soon as you turn on a cold computer, that is a sign of an more serious isues. Please advise if that is happening.