Can't enter BIOS (Inspiron 14 7447 / Win 10)

Dear Friends,

i bought Inspiron 14 7447 last year, here's the spec:

i7-4710HQ 2.5 GHz
8 GB RAM
Windows 8.1 SL

i'm not sure if it's after the OS upgrade (from Win 8.1 to Win 10)
-or- after the BIOS upgrade (from A00 to the latest A07)

When i press F2 button to enter BIOS, there's a blue colored progress bar, very slow, and after finished, it stuck with blank screen.

it's been a while since the last time i entered the BIOS, so i don't know which one is the cause, OS upgrade or BIOS update.

Please help me. Thank you very much.

Bumping Topic..