I need help with acer e1-521 windows installation and bios update.

I've been trying to install windows 7 after realizing windows 10 is slowing down the laptop. It didn't want to load drivers in installation (installing from usb). I've tried to switch the usb ports and such and it didn't work. I've tried messing with bios(1.08 version) setup but it doesn't have an option to choose between UEFI and Legacy neither it has Secure Boot option. After realizing that I've decided to update bios(1.12 version) driver which ended up with restarting laptop (as usual) and when it turned back on all I could've seen it black screen with cursor (its been like that for at least 30+ mins). What should I do?