Inspiron 15 3542 unable to update bios version

Hello,

I have been unable to update the bios on my inspiron 15 3542 from the A12 version released in 2016 to A13 and A14 respectively, i tried updating it from windows 7 and 10 and also from a dos bootable usb but every time the same thing happens again and again, it reboots the pc as if the bios is going to be updated but nothing happens and instead it just boots into the windows and the bios version is always A12. I tried with Intel Virtualization Technology and other features in the bios setup enabled and disabled. I also tried to downgrade or reinstall the same version (A12) again but it doesn't allow me to, it just says it's only possible to install and new version than the one already installed.

The reason i'm trying to update the bios is due to the original problem i'm having with my laptop explained in the link below (Another discussion i started).
https://www.dell.com/community/Inspiron/Inspiron-3542-Shuts-down-by-its-self/m-p/6197933#M37914
In summery my laptop unexpectedly shuts down or crashes (it literally goes from on to off with no errors what so ever) after 20 to 30 minutes of running normally and after i turn it on again the same thing happens again after the exact same time. No it's not an overheating problem as i did check all the temperatures and they were all bellow 40°c right before the crash and also not an os problem as i tried from windows 7 and 10 and also from the bios setup and the integrated hardware diagnosis (it runs fine with no errors in any hardware).

I believe the fix to my problem is in upgrading the bios version to the latest one as dell described the A13 version as urgent and fixed some cpu related issues and i hardly found a topic on the internet saying that issue may make the pc shut down unexpectedly which is what's happening to me or go to sleep.

Any help would be appreciated.