tv LG 4K TV Doesn't login to Windows!

[PK_Jr.]

Hello guys, i have an issue! i own a LG tv super UHD4k model number <<SJ850V>> I recently format my pc (Windows 10 Pro) and when i connect tv to pc through HDMI i can't get into windows! It Asks my mail's password and when i put it and the circle dots starting to roll on to get into windows then the screen goes black for a couple of seconds and it goes me back to login screen and asks for my password all over again and again! In the past (Windows 10 Pro too) i was disconnecting my Pc Monitor (BenQ) so only HDMI was on and i was getting into windows with my TV through <<Safety Mode>> for once so my GPU (gtx 1070) can "read" it and then everything was normal with both screens connected! But now i can't do that cause TV says i don't have signal until i get into login screen so it comes up and asks for my password again! I can't get in safety mode cause screen says "No Signal" during post!! MY NERVES ARE NOT VERY WELL! Sorry for my syntax, i am from Greece!