LOUD BANG NOW A SCRAPING NOISE

We had not used the car for a 3 weeks and had left it on the drive, on attempting to use the car battery had gone flat , on recharging the battery we discovered a clunking noise,we were advised that the power steering fluid may need topping up. We bought the recommended fluid as advised in the car log book,but we still had the clunking noise, we left the car for a further week then on using again,there was a bang and it now sounds like there is a metal rod scraping the floor ,but on having a quick look under the car we cannot see anything hanging down,at the moment we dare not use the car.