Aspire 3 N20C5 When I switch on laptop it pops up an error message called No Bootable Device Error

Danula

When I switch on my laptop it pops up an error message called "No Bootable Device". To fix this I have done the all tutorials on YouTube but doesn't work. In every YouTube video, it's showing to switch Legacy mod from UEFI. But there isn't a mod known as Legacy when I'm trying. And in the boot order, there is no showing disks of my laptop. please help. My Laptop is model no. N20C5 laptop Aspire 3

[Edited the thread to add model name to the title and add issue detail]

Puraw

https://community.acer.com/en/discussion/701845/aspire-3-n20c5-when-i-switch-on-laptop-it-pops-up-an-error-message-called-no-bootable-device-error

This the ACER ASPIRE 5 (N20C5) Laptop, Core i5 11 Gen, Win 10 OS? This laptop does not support Legacy. The boot error indicates that the bootloader is either corrupted or missing or there are issues with your 2.5" Sata-3 HDD or M.2 SSD, The Ram modules (2x4GB DDR4?) also need checking if bad or have a bad connection. Open the laptop, disconnect the battery and check the connections of the HDD (if you have one), SSD and Ram modules and reconnect the battery, reboot. If still the same error, I recommend bringing the 2020 laptop to Acer Services in your country to reset BIOS and OEM OS for a small service fee.