cannot access BIOS (goes directly in Linux login screen)
 

My Linux debian jessie works fine on my computer but...
I tried to get into my BIOS and I couldn't anymore...
I usually press DEL or F2 but if I do that it doesn't go into BIOS but it stays blank (black screen) then seems like frozen there whatever I would try. If I restart the computer and don't press any keys then it goes into debian jessie and loads the Linux fine.
I know it sounds like not a Linux problem but it only happened to me now with the Debian jessie and never before.
Any ideas?

It's not a linux issue. You just need to look up your system documents for getting into the bois. I had issues remembering how to get into my bios once. I googled it and bingo I am in. sometimes you need to wait for a certain image or text to be displayed before you can hit the key to enter into the bios.

maybe UEFI, not BIOS?
some actual info on your setup?

Do you shutdown linux or go to some saved state?

Be sure to shutdown. Let it power down fully and then pull ac plug. Then press power button a few times.

Then return power and boot. If you have a wireless keyboard it may be that you have to get it going with some keystrokes before bios entry.

Some bios's are just junk.

Various BIOS manufacturers use different keystrokes. I've seen F12, Esc, and others. And if you're using UEFI, there is no BIOS, so you have to use whatever the manufacturer provides to get to boot options.

Look in your mobo book:-

If you don't have the mobo book than look up your exact mobo online for the pdf.

did you try esc key, google your make and model with key words access BIOS key to access BIOS and such things as that yet?

when you do find it press and hold it as soon as you just turn on the pc