Burner Operates but doesn't read -no extenral cd mount

Bought HP Touchsmart 300 at a pawn shop. System had been wiped and began from scratch (new user). Software works fine but when I insert CD or DVD it doesn't detect it. I know it's a hardware problem but the only advice I've found is to clean and readjust the "toggle" the reader arm. Well cd/dvd player doesn't have a slide out disc plate. It feeds and ejects from the pc itself. Can I fix it or should i just buy an external burner?