Question laptop boot issue

Jul 28, 2022

My lenovo Ideapad 100 starts up, shows my the EXITING PXE ROM error screen, starts beeping and then boots up normally.

Let me explain, when I try to access the BIOS menu and press Fn+F2, It starts beeping unstoppably until the OS Boots up. I'm on Legacy Support and want to switch to UEFI Mode. Between this incident, the EXITING PXE ROM error is also shown. But surprisingly, the OS still boots up completely normally. I cannot enter the BIOS Menu and I have to watch the PXE screen every time I start my laptop. It wastes a LOT of time and it's SUPER ANNOYING.

My laptop also gives a 10 second delay after starting up and after shutting down (the screen goes black but the power still stays on.)

Please send help immediately.
Thank you Veerry Much.