Every time I accelerate the gas a yellow light comes on that says "hill start assist not available?

I just bought this car 1 month ago. No problems until yesterday and every time I accelerate the gas a yellow light comes on that says "hill start assist not available ".I was going to have my step-dad look at it, he's an old school mechanic. I drove it about 30 miles last night, pulled into park, turned off the car and everything stopped working. No lights, no window power, no dash lights. I went out this morning to check and my car was fine, all power was back. Now I'm afraid to go anywhere.