Forerunner 945 not start, black screen.

Hello,

Today, after my swimming training, I had a one-hour break and wanted to start my bike training. However, when I tried to start my training, my watch was very slow to respond. I pressed the start button, but it took 10-30 seconds to react.

When I got home, I reset my watch, but now it won't start at all. I've tried all the reset and master reset options, but nothing has worked. I also attempted to connect it to my PC, but there's no response, and Windows doesn't recognize the device.

Do you have any suggestions on how I can fix this, or is there anything else I can try?

Thank you.