Dell bios version A06 » how to boot from a flash drive?

Question

Dell

Good day to all.
Got a laptop:

1. bios version A06
   
2. product name ispirion 5749
   

With Ubuntu preinstalled.
Now the question arose about reinstalling the OS, changing to Win7.
The first problem I encountered was booting from a USB flash drive, I can’t boot from a USB flash drive under any pretext, help someone who dealt with this version of biosa A06.
I did the following manipulations:
in the Boot menu => file browser add boot option - chose USB: mass storage device => autorun.inf (tried setap.exe) The
download did not go, it gave an error:
invalid signature detected.
Check Secure
Boot
Policy in Setup

Answer 1

solved here forum.ru-board.com/topic.cgi?forum=81&topic=8755