Since you have an Ultrabook, you wouldn't probably be able to pull out the battery. So, you should go in a different way, I guess. :) If the laptop doesn't have a warranty, you could open it while the power cable is unplugged. Then, try to localize the 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.