Thanks for the screenshots, but they do not show any USB drive is recognized by the system, so you want to look into solving that.
If you haven't already, check the user manual page 68 as xyzbird mentioned and follow steps 1, 2, and 3 to download the latest bios, unzip it, copy to a USB flash drive, connect to your notebook, and re-enter the bios to flash.
https://dlcdnets.asus.com/pub/ASUS/GamingNB/GU501GM/E13724_GU501GS_GM_A.pdf?_ga=2.120102984.15811329...
Feel free to discuss more, but if you have any interest in talking or chatting with ASUS support in the U.S., check the support page below.
https://www.asus.com/us/support/callus
Also, if you didn't already know, there is a small chance you can kill your system if something goes very wrong with the bios flash (the system would need to be sent back for repair in this case and make sure you're still under warranty, otherwise, you may want to reconsider if it's worth taking that chance), so you may want to reconsider flashing the bios or wait to try it another time if better.
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Although some people don't like the idea of flashing the bios through Windows, if you're having any problems with the bios EZ Flash 3 Utility, consider trying the ASUS Winflash utility inside Windows which should be a little easier to use and will restart Windows to flash the bios.
