My car was fine, but a week and a half later the dash light on when I started it

Hello and thank you for responding. The only performance issue is it's hard steering as if i'm losing power steering and hardly no power to drive, but once I get going I'm good until I get to a stop light and the same thing happens again. On the highway I'm good, but I feel the difference in the breaking. I will take it for an hour highway drive tomorrow morning. This morning I called triple A and the tech came out and checked my battery, alt etc., and printed me a ticket. It stated, the battery good, starter test good, but the charging system is high voltage. He said, my computer need resetting. I am going to drive it like you said and hope those lights go out. Thank you!