Boot problem

hello I saw lots of answers for this question but nothing seems to work i cleared my nvidia drivers with ddu tool and reinstalled them.now i get a blue screen with moise cursour on it i know i need to enter in safe mode but i don’t know how.i’ve tried everything (f8,force *** down) but nothing changes i have an alienware x51r2.it shows a loading dell screen and the only keys that work are f2 and f12. pleasee help.I tryed almost everything Please help me