SYSTEM WON'T BOOT AFTER automatic BIOS UPDATE (1.2.7.) dell inspirion 7559

Hello, today i got the messagge from dell support application about new driver ready to install. Turned out it was a bios update (1.2.7). Everything was fine, after installation, computer has rebooted, the dell logo appeared as usuall and it stoped right there. It's just black screen with dell logo and it won't boot. 

I have acces to bios setup. I've tried to downgrade the bios to previous version (1.2.5) from usb flash but it doesn't work either. 

Also I've read that dell laptops have bios recovery option (according to dell site mine has) which you prompt by pressing ctrl + esc button, it also doesn't work. Maybe becouse I have an ssd disc and windows is installed on it? I've called the technical support and they said i should reinstall my windows which i don't want to do becouse of the important data on it.

If anyone of you could help me I would be very thankfull.

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