Are you talking about a laptop or it's a desktop computer that you have in mind? If it's a laptop, then you could try to reset the BIOS. You could do so by pulling out the CMOS battery. You have to do that after you have pulled out the battery and the power cord of the laptop. Open the lid and localize the CMOS battery which lies next to the processor and it looks like a watch battery. If you have another CMOS battery, you can replace it with that. If you don't, leave your current battery aside and wait for some minutes for the electricity to discharge. Then, plug the CMOS battery back in and the power cord. Try to boot your laptop again.