Suggest a quick 'Google' on (unspecified) make and your symptom (eg HP Pavillion da-de-da and no BIOS screen shown on bootup, or whatever)? I have heard of some laptops where you need to go through a battery removal/power cycle to clear a 'blockage' and again a Bios battery removal or clear the bios with another type.
Of course, it could be b******d (technical term) - have you dropped it in the bath or on the floor?
