The F2 key is just used to open the PC in Setup Utility mode. These are the steps I used, hopefully it works for you:
- Go to your Start Menu, Select Power and Restart
- Your PC will begin to restart, while it is doing this hit the F2 key repeatedly to open Setup Utility
- Once Setup Utility is launched select "Advanced" from the top menu
- Under Advanced is Battery Life Cycle Extension, set this to "Disabled"
- Select "Exit" from the top menu, then choose "Save Changes and Reset"
Your PC will now reset again, and should charge back up to 100% battery power.