How do I fix a non-responsive Apple Watch?

Which Apple Watch do you use?

If this is an older model, has the battery ever been replaced by Apple?

If you connect your watch to the charger and an original 20W Apple Power adapter for about 30min, does the watch start automatically?

...

If you connect your Apple Watch to its charging cable and you don't see a lightning bolt on your watch:

• Make sure you're using the Apple Magnetic Charging Cable or USB-C Magnetic Fast Charging Cable that came with your watch.
• Make sure to plug the charging cable all the way into the USB Power Adapter, then plug the adapter all the way into a power outlet.
• Reposition the back of your watch on the charger. When the charger's magnets align correctly with your watch, a lightning bolt should appear on the watch face.
• Make sure that the back of your watch and the magnetic charger are clean. Completely remove any plastic wrap from both sides of the charger. 
• Try a different Apple Watch Magnetic Charging Cable or USB-C Magnetic Fast Charging Cable, and a different USB Power Adapter. 
• Leave your watch connected to its charger for a while. If your watch is out of power, you might need to wait up to 30 minutes for the lightning bolt to appear.
• If your watch still won't charge, force it to restart: press and hold both the side button and Digital Crown for at least 10 seconds, or until the Apple logo appears.

...

copied from: If your Apple Watch won't turn on or won't charge - Apple Support

You can see an estimate for getting the battery replaced by Apple on this Apple Watch Service & Repair page:

Apple Service and Repair for Apple Watch - Apple Support

If other parts of the hardware are damaged, the price of getting the whole watch replaced is almost as high as the costs for a new Apple Watch.

Step 1. Force Restart.

According to Apple:

To force restart your Apple Watch, press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo ().

Step 2. Reset Watch.

How to reset your Apple Watch:



1. Put your watch on its charger and keep it there until you complete these steps.
2. Press and hold the side button until you see Power Off.
3. Press and hold the Digital Crown until you see Erase all content and settings.
4. Tap Reset, then tap Reset again to confirm.
5. Wait for the process to finish, then set up your Apple Watch again. When asked, restore from a backup.

NOTE — Erasing all content and settings erases all media, data, and settings from your Apple Watch, but it does not remove Activation Lock. To remove Activation Lock, unpair the watch first. Before your watch is erased, a backup of its contents is created on your iPhone.

Step 3. Connect Watch.

Then make sure both devices are in close proximity with the following settings:

• AirPlane turned off
• WiFi turned on
• Bluetooth turned on

Click ▶︎ Connect/Pair your Watch for detailed instructions.

Need more help?

• United States: 1-800-APLCARE.
• Contact Support.
• Apple Watch Support.
• Apple Watch User Guide.

Good luck! 👋🏼😉

Smiliñ 😎 Brian | Community Volunteer

I use the apple watch 7 series. The battery has never been replaced from Apple.

It does not start and does not show anything. I will be taking it to Apple this Saturday to see if the Apple Natick can help me out. Also nothing pops up on the watch.

I already tried to force restart it but nothing pops on the screen.