Bump to old question.
I had the same problem with my old Samsung NP300E5X (NP300) (BIOS version P07RAC). I have changed something in BIOS (I guess something to do with secure boot or UEFI, anyway I don't know what's the difference, sorry) and it was impossible to enter to BIOS by F2 button.
Problems were like:
- you can't enter to BIOS by pressing F2, but you can enter Windows Recovery Mode (F4 or F10, nothing interesting here to solve the issue),
- you can't update BIOS by Samsung BIOS update utility, because you have already got the latest version (utility stops working saying this),
- shorting RTC reset, BIOS crisis contacts gives no effect (contacts next to RAM on the motherboard),
- external USB-keyboard gives no effect,
- if you disconnect any HDD - your notebook is just stuck in endless bootloop (you see Samsung logo-F2-for-BIOS-F4-for-Recovery, 3-2-1, reboot). No way you can enter BIOS here.
What your aim should be: **to reset all BIOS settings to default**. We are going to reflash the same version P07RAC, but without Samsung BIOS update utility.
1) Open the BIOS update tool from Samsung. Click on «Download» instead of «Update». It offered "ITEM_20130402_1070_WIN_P05RAJ.exe" (I don't know, why there is "RAJ" not "RAC", but this is for NP300E5). If you have a different notebook, the file name should be something like that, so, keep Googling your needed «ITEM_..._version.exe».
2) Run the file "ITEM_20130402_1070_WIN_P05RAJ.exe". The program decompresses several files to "C:\Users\<myuser>\AppData\Local\Temp\__Samsung_Update" The program refuses to update the BIOS because it is the latest version, and then deletes the files. I copied the files before closing the program. They contain the ROM and the SFlash64.exe utility, and some other files required for flashing.
3) Run cmd.exe as an Administrator and run this exe from copied files **SFlash64 /n /s /sa /ips /exit /file P07RAC.rom** (notice, here "P07RAC" not "P05RAJ). Also, you may check "SFlash64 -help" for help.
This will flash over the BIOS with the same version resetting all settings.
So, you can enter BIOS by F2 button as normally.
Summarized from here: http://forum.notebookreview.com/threads/...