Why do i have to press F1 when start my computer?

Never had to b4 and now to start my computer i have to press F1 how do i fix this?|||Without anymore info, I would say your CMOS battery is dead. Most can be popped out carefully, and replaced. They are usually about the size of a quarter, just a bit thicker.|||If your computer is 4-5 years old or older, then it's the CMOS battery. On desktops, they easy to replace on the motherboard. For laptops, much more difficult as you have to usually take the machine apart...