1. First, check whether the TV is properly connected to the power supply and make sure that the TV is powered on.
2. Check and make sure that the TV remote control has enough battery power. If replacement is required, please try to open the main menu again after replacing the new battery.
3. Restart the TV. Some TVs need to be restarted to open the main menu normally. You can unplug the TV, wait a few minutes, then plug it in again and restart the TV.
If none of the above methods can solve the problem, you can try to update the TV software. You can find this option in the TV Settings menu and update the software. In addition, you can contact TV manufacturers or after-sales service agencies for technical support.
In short, in any case, if the TV still can't display the main menu, I suggest you contact professional TV maintenance personnel in time for further troubleshooting and maintenance.