I have a Dell Inspiron 3521 laptop. I can access the BIOS using F2 during boot. But inside BIOS I can't change any setting as the keyboard doesn't seem to type. The CPU fan seems to rotate fast inside BIOS. Tried to upgrade BIOS but it tells me to plug both AC adapter and battery and the laptop doesn't switch on with the battery plugged. I use it with direct current only. Please help.