Assuming that you are still wrestling with this, you can do the hard reset without a computer, but you can't update the firmware.
I agree that you should try the "two button" reset. It will reset any menu items that you have stored, and it will put your camera back to factory settings. The reset buttons are the "i or information" button and the "menu" button. Hold them both down at the same time. You will probably get a message on the display that asks if you really want to that. Answer OK or whatever allows it to proceed. After the reset, I would probably take the battery out for about 30 seconds, but don't ask me why.
Let us know if that works. If not, maybe we can suggest a way that you can get the Lemurs in focus by using P (Program Mode) and Auto-ISO by choosing ISO 100 with a maximum ISO of up to ISO 3200 with a minimum shutter speed of 1/60. That would be my preference anyway over flash if it's a possibility.