HP Pavillion dv7 won't enter BIOS. No matter which key (Esc,F9,F10,F1,F2 etc) is pressed

HI,

I have HP pavilion dv7 which won't let me in BIOS to change boot order.  

I have windows 8 32 bit installed and it keep booting normally no matter which key  (Esc,F9,F10,F1,F2 etc) at start up, is pressed or keep pressed.. it wont stop booting and wont let me in BIOS. All it does it that if keys are pressed it will start beeping but then boot anyway.

I want to boot it from USB and install WIndows 8.1 64 bit.  

plz help.

Thanks