Try this, when you restart your laptop and get the first initial screen, press the Pause button on your keyboard. It will pause the screen so you can read which button to enter BIOS or Boot Options. Also, try the default DEL button to get into BIOS.
it does't show any initial screen when i start, after black screen it stuck on starting windows, i have tried all the f keys and dell key but it could,t show bios except safe mode. in safe mode it hang on